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Graphical abstract Healthcare waste management is considered one of the biggest challenges that the world is going to face in the future. This threat is becoming reality owing to the worldwide sharp rise in healthcare waste generation particularly during the current COVID-19 pandemic. Like many other environmental crises, hospital plastic waste management is an area that got very little attention despite being highlighted in the literature, local media, as well as in international electronic and print media. This mini-review was conducted to assess the overall prevailing situation regarding hospital plastic waste management in Pakistan. Several illegal and unethical activities have been observed regarding hospital plastic waste management in Pakistan which includes unhygienic recycling, repacking of used hospital plastic items, open dumping on land, and disposal of hospital plastic waste in the ocean. To improve these conditions, suggestions have been made regarding the better management of hospital plastic waste.

Drought is a global phenomenon that can occur in any ecological zone and render significant damages to both the natural environment and human lives. However, hydro-climatic stresses are growing distinctly in the arid zones across the globe. Literature suggests that the analysis of a long-term data-set could help in strengthening of mitigation planes and rationalization of disaster management policies. Thus, the present study is aimed to analyze the evidence-based historical drought events happened in arid-zone Badin, Pakistan and predict its occurrence and severity for the next 82 years (2018-2099). Drought indices viz standardized precipitation index and reconnaissance drought index have been used to detect the severity of the drought events. Thirty years (1988 to 2017) past data of precipitation and temperature were used to categorize the drought severity and validated against the local data. Climate projections based on RCP 4.5 and 8.5 made at 25x25 km resolution used for future drought analysis. The results demonstrate that the region faced severe to extreme drought in 1990-91 and 2001-04. While, in future 2020-21, 2036-37, 2038-39 would be the extreme driest years under RCP 4.5 and 2029-30, 2089-90 under RCP 8.5. Further insight revealed that the average annual temperature has increased and precipitation has decreased w.r.t the base year 1988. It is concluded that drought detection with SPI and RDI is suitable and drought prediction with the RCP 4.5 and 8.5 could be a better option.

Increasing salinity levels in the tidal rivers are becoming a significant challenge to inland water quality. Salinization of the adjoining water resources and agricultural lands have prompted the water managers to optimize the solutions for mitigation of adverse effects. Keeping this in view, a hydrodynamic model coupled with a water quality model was used to analyze the propagation of tides from the Arabian Sea into the Indus River and their subsequent effect over longitudinal salinity distribution. Field observations of hydraulic parameters and salinity were used for validation of the model predictions in dry (no river flow) and wet (specific river flow) hydrological conditions. Results suggest that the tidal amplitude dissipates landward; salinity intrudes about 58 km (near Dandari) into the Indus River Estuary (IRE) at spring tide. Salinity in the proximity of Dandari point is sensitive to variations in fresh water supplies. A complete neap-spring tidal cycle was chosen for scenario-based evaluation of the impact of fresh water over the longitudinal salinity distribution. A daily river discharge 250 m3/s was found optimum for limiting the salinity interface (≤1) up to 31 km from the estuary mouth. In addition, tidal inlet modifications based on the theoretical framework of stable channel design combined with the optimum river discharge were tested. The cross-sectional modifications based on the regime/Lacey theory proven better and salinity interface was further pushed back up to 27 km. Thus, it is maintained that synergic impact of the optimized freshwater quantity and the estuary mouth modifications are considered as one of the pragmatic solutions for control of salinity intrusion and achieving the specific environmental conditions along the alluvial estuary.

The Indus River Basin is the fourth-largest irrigation system in the world, contributing up to 25% of Pakistan’s gross domestic product and 90% of its food production. Various kinds of water users (i.e., rural, urban, subsistence, and commercial irrigated agriculture) exist in the catchment. The rising local population—in conjunction with climate change and the need to meet minimum flow requirements—will significantly exacerbate the complexity of future water resources management in an already water-stressed sub-catchment. The water evaluation and planning system (WEAP) model is widely used to analyze the complex water resources systems and to examine supply and demand management strategies. In this study, a scenario analysis is conducted using WEAP to assess the impacts of possible future water demands on Indus water resources. For each scenario, the water resource is compared to the baseline year of 2015, then analyzed according to two growth rate scenarios. These simulations may help in understanding the potential water management problems of the future. It is estimated that by 2040 if population continue at the census 2017 growth rates, the water demand of Punjab and Sindh provinces will increase to 192.7 billion cubic meters, which is more than the current entitlements and availability.

Impacts of climate change and human-made interventions have altered the fluvial regime of most rivers. The increasingly uncertain floods would further threaten the flow delivery system in regions such as Pakistan. In this study, an alluvial reach of the Indus River below Kotri barrage was investigated for the geomorphologic effects of sediments deposited over the floodplain as well as the influences on the downstream flood-carrying capacity. The hydrodynamic modeling suite HEC-RAS in combination with ground and remotely sensed data were used to undertake this analysis. Results suggest that the morphology of the river reach has degraded due to depleted flows over a long period and hydrological extremes that have led to excessive sediment deposition over the floodplain and an enhancement in flood water extension possibility over the banks. A deposition of 4.3 billion cubic meters (BCM) of sediment increased the elevation of the channel bed which in turn reduced a 17.75% flood-carrying capacity of the river reach. Moreover, the excessive deposition of sediments and the persistence of low flows have caused a loss of 48.34% bank-full discharges over the past 24 years. Consequently, the river’s active reach has been flattened, with a live threat of left levee failure and the inundation of the populous city of Hyderabad. The study would gain insights into characterizing the impacts associated with a reduction in the flood-carrying capacity of the alluvial channel on account of the inadequate sediment transport capacity after heavy flow regulations.

Changes in precipitation and temperature directly affect the demand and supply of freshwater. This chapter presents and compares changes in these two climatic variables in the three major mountain ranges of Pakistan (Hindu-Kush, Karakoram, and Himalayan). The non-parametric Mann-Kendall, Sen’s Slope Estimator, and Mann-Whitney U-test were applied to investigate changes in the precipitation and temperature time-series for the period from 1975 to 2014. The gauge weight method was used to estimate the areal average values of both climatic variables. The time-series datasets were classified into two equal periods to enable assessment of relative changes. Results indicated that the average annual temperature had an increasing trend in all mountainous ranges, with the highest warming trend in the Karakoram range (0.08 °C/decade), followed by Hindu-Kush (0.04 °C/decade) and the Himalayas (0.03 °C/decade). The results of seasonal trend analysis indicated the highest warming trend of the spring season in the Hindu-Kush range (0.33 °C/decade), followed by Karakoram (0.28 °C/decade) and the Himalayas (0.17 °C/decade). A cooling tendency of summer temperature was found in the Karakoram range (−0.10 °C/decade), followed by the Hindu-Kush range (−0.09 °C/decade), while a warming trend of summer temperature was found in the Himalayas. Overall, a decreasing trend of total precipitation was found in the Himalayas, with a significant decreasing trend of annual (38.90 mm/decade) and spring (14.88 mm/decade) precipitation. On the contrary, annual precipitation showed an increasing trend in the Hindu-Kush (13.88 mm/decade) and Karakoram (11.86 mm/decade). Overall, our investigation confirms that the climate of the region is already changing, with an increasing trend of temperature across all mountainous ranges and a decreasing tendency of precipitation in the Himalayas.

Recently, the Global Precipitation Measurement (GPM) mission has released the Integrated Multi-satellite Retrievals for GPM (IMERG) at a fine spatial (0.1° × 0.1°) and temporal (half hourly) resolutions. A comprehensive evaluation of this newly launched precipitation product is very important for satellite-based precipitation data users as well as for algorithm developers. The objective of this study was to provide a preliminary and timely performance evaluation of the IMERG product over the northern high lands of Pakistan. For comparison reference, the real-time and post real-time Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) products were also evaluated parallel to the IMERG. All of the selected precipitation products were evaluated at annual, monthly, seasonal and daily time scales using reference gauges data from April 2014 to December 2016. The results showed that: (1) the precipitation estimates from IMERG, 3B42V7 and 3B42RT products correlated well with the reference gauges observations at monthly time scale (CC = 0.93, 0.91, 0.88, respectively), whereas moderately at the daily time scale (CC = 0.67, 0.61, and 0.58, respectively); (2) Compared to the 3B42V7 and 3B42RT, the precipitation estimates from IMERG were more reliable in all seasons particularly in the winter season with lowest relative bias (2.61%) and highest CC (0.87); (3) IMERG showed a clear superiority over 3B42V7 and 3B42RT products in order to capture spatial distribution of precipitation over the northern Pakistan; (4) Relative to the 3B42V7 and 3B42RT, daily precipitation estimates from IMEREG showed lowest relative bias (9.20% vs. 21.40% and 26.10%, respectively) and RMSE (2.05 mm/day vs. 2.49 mm/day and 2.88 mm/day, respectively); and (5) Light precipitation events (0–1 mm/day) were usually overestimated by all said satellite-based precipitation products. In contrast moderate (1–20 mm/day) to heavy (>20 mm/day) precipitation events were underestimated by both TMPA products while IMERG was found capable to detect moderate to heavy precipitation events more precisely. Overall, the performance of IMERG was better than that of TMPA products. This preliminary evaluation of new generation of satellite-based precipitation estimates might be a useful feedback for sensor and algorithm developers as well as data users.

The northern part of Hindukush Mountains has a perplexing environment due to the influence of adjacent mountains of Himalaya, Karakoram, and Tibetan Plateau. Although reliable evidences of climate change are available; however, a clear knowledge of snow cover dynamics in the context of climate change is missing for this region. In this study, we used various remotely sensed (TRMM precipitation product, while MODIS temperature and snow cover products) and gauge-based datasets to quantify the spatiotemporal variability of climatic variables and their turn effects over the snow cover area (SCA) and river discharge in the Swat watershed, northern Hindukush Mountains, Pakistan. The Mann–Kendall method and Sen’s slope estimator were used to estimate the trends in SCA and hydro-climatic variables, at 5% significant level (P = 0.05). Results show that the winter and springs temperatures have increased (at the rate of 0.079 and 0.059 °C year−1, respectively), while decreasing in the summer and autumn (at the rate of 0.049 and 0.070 °C year−1, respectively). Basin-wide increasing tendency of precipitation was identified with a highest increasing rate of 3.563 mm year−1 in the spring season. A decreasing trend in the winter SCA (at the rate of -0.275% year−1) and increasing trends in other seasons were identified. An increasing tendency of river discharge on annual and seasonal scales was also witnessed. The seasonal variations in discharge showed significant positive and negative relationships with temperature and SCA, respectively. We conclude that the future variations in the temperature and SCA in the higher altitudes of the Swat watershed could substantially affect the seasonality of the river discharge. Moreover, it implies that the effect of ongoing global warming on the SCA in the snowmelt-dominated river basins needs to be considered for sustainable regional planning and management of water resources, hydropower production, and downstream irrigation scheduling.

Sea level rise (SLR) in response to looming climate change is being considered as a major impediment to coastal areas. Acute wave activities and tidal propagations of semi-diurnal to mixed type are impairing the morphology of the Indus Delta in Pakistan. In this study a synthetic approach has been adopted using multi sensor satellite and ground data in order to integrate the individual effect of topography, oceanic activities and vegetative canopy for deduction of a synergic impact over the morphology of the Indus Delta creeks system from 1972 to 2017. Geomorphologic anomalies in the planform of fourteen major creeks were explored. Spatiotemporal variations suggested that a substantial amount of the delta alluvium had been engulfed by the Arabian Sea. On average, the creeks located on the right side of the Indus River were relatively less wide (3.9 km) than those of on the left side (5.2 km). Zonal statistics calculated with topographic position index (TPI) enabled to understand the tide induced inundation extents. The mangrove canopy on the right side was found greater, which is why tidal basins on that side experienced less erosive activities. Thus, it could be maintained that the coastal sedimentary processes may be monitored effectively with the remotely sensed data and temporal pattern of changes can be quantified for future planning and mitigation of adverse effects.

Supply of quality water has been recognized as one of the water management practices. Clean water is not only essential for drinking and irrigation but also affects eco-services, groundwater aquifer and soil conditions. Hyderabad, a highly populated city of Pakistan is consuming large quantities of water and also disposing its untreated sewage and comingled solid waste in Phuleli canal. Similarly, many encroachments along the banks of Phuleli canal are directly impairing the water quality due to disposal of wastewater and other rejected materials. This canal irrigates Tando Muhammad Khan as well as some areas of district Badin. A review of many studies revealed that maximum of physio-chemical and biological parameters especially fecal Coliform (between 100-1600 MPN/100ml) and metal ions (Fe 1.90, Cd 0.004, Cr 0.082, Pb 0.045 and As 0.50 mg/l against WHO (World Health Organization) standards) were exceeding the prescribed permissible limits.This contaminated water is deteriorating the water quality and threatening the public health. Due to inadequate measures and apathy from responsible departments, water quality is being compromised especially during winter season, when low flows are released from Kotri Barrage, Kotri, Sindh. Without positive interventions and adherence of integrated approach, it is hard to ensure public health and sustainability of the canal system and agriculture depending upon this

Natural and anthropogenic factors directly determine the hydromorphologic and ecologic equilibrium of riverine environment. The present study was designed to detect the hydromorphologic characteristics of Indus River Estuary (IRE) using medium and high spatial resolution multispectral satellite imagery along with field data. Qualitative (visual) and quantitative (analytical) analysis was undertaken, and accuracy of each method as well as remotely sensed data was assessed. Single-band density slicing method was used for water bodies, while multiband supervised and unsupervised classification methods were adopted for the identification of hydromorphologic habitat along with key ecologic features of the IRE. The analysis of satellite imagery showed that the shortwave infrared-2 (band 7) of Landsat-8 Operational Land Imager (OLI) sensor performed better than its visible bands for delineating water bodies. The overall classification accuracy was 89%. Supervised classification with the maximum likelihood algorithm performed better for OLI imagery (30 m) than high spatial resolution RapidEye (5 m) imagery. However, unsupervised classification method was not suitable due to the significant overlapping of inter- and intra-class pixels. Overall, due to its adequate spectral range Landsat OLI imagery was utilized for monitoring of terrestrial water bodies and their morphologic features. Thus, we recommend that selecting the spatial resolution of the imagery should be based on the size of the objects to be recognized.

The riverine ecosystem is dependent upon the supply of fresh water but the decrease in flows weakens this connection. It gradually leads to impairment of ecologic as well as geomorphologic settings of a riverine ecosystem. Keeping this in view, the present study was designed to assess the contemporary evolution of the Indus River Estuary (IRE) under forced hydrological conditions. An account of transitions in the eco-geomorphologic response of the IRE was synthesized using satellite imageries from 1972 to 2016 and interpreted with the ground observations. Due to flow regulations, an 80% decrease in average annual flow and 50% dampening of flood peaks have altered its hydrological regime. These pronounced hydrological shifts have also played a significant role in the modulation of channel morphology. Similarly, the morphological configuration of the estuary like the length and width of the channel have also increased by 11% and 29%, respectively, and the rate of erosion was more than the deposition. After experiencing significant variations in the rate of lateral migration, the channel has started creeping in a south-eastern direction dominantly since 1993, with an average rate of migration of 44 m/yr. Correspondingly, the riparian landscape has also evolved coherently with a notable competition between bare land and the vegetative cover. Trade-offs between the river hydrology, channel morphology and landscape ecology were understood with a correlation matrix and interpreted with plausible causes. It would help the policymakers to assess the overall ecological health of the IRE and contribute the experts working on designing a framework for the study of system dynamics.

The performance evaluation of satellite-based precipitation products at local and regional scales is crucial for modification in satellite-based precipitation retrieval algorithms, as well as for the provision of guidance during the selection of substitute precipitation data. This study evaluated the performances of three Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) products (3B42V6, 3B42RT and 3B42V7) with a reference to rain gauge observations in the Hunza River basin, northern Pakistan. Multi-spatial (pixel and basin) and temporal (daily, monthly, seasonal and annual) resolutions were considered for performance evaluation of TMPA products. Results revealed that the spatial pattern of observed precipitation over the basin was adequately captured by 3B42V7 but misplaced by 3B42V6 and 3B42RT. All TMPA products were unable to capture the intense precipitation events. On the daily time scale, the performance of TMPA products was very poor over both spatial scales. 3B42V6 underestimated the precipitation (31.25% and 44.27% on pixel and basin scales, respectively). By contrast, 3B42RT significantly overestimated the precipitation (47.91% and 38.62% on pixel and basin scales, respectively), while 3B42V7 showed overestimation (17.30%) on pixel scale and slight underestimation (6.24%) on the basin scale. On the seasonal scale, TMPA products showed significant biases with observed precipitation data. We found that the TMPA products performed relatively better on monthly and annual time scales and overall performance of 3B42V7 product was better than that of 3B42V6 and 3B42RT. The bias in 3B42V7 was improved by 85.90% compared with 3B42V6 and by 116.16% compared with 3B42RT. Thus, it is concluded that the TMPA products were unreliable to capture the intense precipitation events and retain high errors on daily and seasonal scales. Therefore, caution should be considered while using these precipitation estimates as a substitute data in hydrology, meteorology and climatology studies in Hunza River basin. However, due to the reasonable performance of monthly and annual 3B42V7 estimates, these can be used as an acceptable substitute for applications in the region.