The formation of acid mine drainage (AMD), a highly acidic and metal-rich solution, is the biggest environmental concern associated with coal and mineral mining. Once produced, AMD can severely impact the surrounding ecosystem due to its acidity, metal toxicity, sedimentation and other deleterious properties. Hence, implementations of effective post-mining management practices are necessary to control AMD pollution. Due to the existence of a number of federal and state regulations, it is necessary for private and government agencies to come up with various AMD treatment and/or control technologies. This review describes some of the widely used AMD remediation technologies in terms of their general working principles, advantages and shortcomings. AMD treatment technologies can be divided into two major categories, namely prevention and remediation. Prevention techniques mainly focus on inhibiting AMD formation reactions by controlling the source. Remediation techniques focus on the treatment of already produced AMD before their discharge into water bodies. Remediation technologies can be further divided into two broad categories: active and passive. Due to high cost and intensive labor requirements for maintenance of active treatment technologies, passive treatments are widely used all over the world. Besides the conventional passive treatment technologies such as constructed wetlands, anaerobic sulfate-reducing bioreactors, anoxic limestone drains, open limestone channels, limestone leach beds and slag leach beds, this paper also describes emerging passive treatment technologies such as phytoremediation. More intensive research is needed to develop an efficient and cost-effective AMD treatment technology, which can sustain persistent and long-term AMD load.

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The outbreak of novel coronavirus (COVID-19) pandemic forced affected countries to implement strict lockdown to contain the spread of this disease before the advent of the vaccine. This containment resulted in social and economic crisis globally. This study evaluated the impact of COVID-19 on three “P” s of sustainability (Planet, People, and Profit) in India. A comparative analysis was conducted by evaluating the available secondary data in different sectors during the pre-lockdown and lockdown period. Seven major air quality parameters: particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), ammonia (NH3), carbon monoxide (CO), and ozone (O3) were studied in six states of India to review the ambient air quality status. Stratified random sampling technique was used in this study for collective portrayal of the country’s air quality. A drastic cutback of the level of PM2.5 and PM10 with significant increase of O3 was observed in the lockdown phase for most of the selected monitoring stations. A significant change in level of PM2.5 and PM10 was observed when t-test was performed in between the pre-lockdown and lockdown period. Improvement of ambient air quality was also observed considering the air quality index (AQI) during lockdown. The trend and volatility of two broad Indian stock market indices, SENSEX and NIFTY-50, were analyzed, and results showed that both the indices have recovered during the forty-day lockdown phase. The potential effects of the crisis on various sectors of Indian economy were assessed in this study, and a set of policy recommendations for these sectors were suggested.