By S N Tripathi and Subrata Hait
The economic shutdown under the Covid-19 pandemic has had two monumental impacts on our environment. It has improved our air and water quality dramatically, and slashed our material consumption, water usage and waste production.
Data from the CPCB (Central Pollution Control Board) and the UPPCB (Uttar Pradesh Pollution Control Board) shows that the Ganga’s water along its most polluted stretch in Uttar Pradesh is carrying more dissolved oxygen and less nitrates. These conditions are conducive to survival of aquatic life. Its biochemical oxygen demand (BOD) has correspondingly fallen, along with the concentration of total coliform, which is a testament to improved water quality. Similar positive developments have been reported for the Yamuna.
There are several reports of the Dhauladhar range in Himachal Pradesh again being visible from Jalandhar, which is 200 km away. Citizens have also seen Mt. Kanchenjunga from Siliguri and Mt. Everest from parts of Bihar during the lockdown. That this has happened after 30 years highlights just how long we have battled severe air pollution.
In terms of our chronically low groundwater reserves, monitoring borewells from Bengaluru report that between March 22 and April 25 the city’s falling groundwater levels improved with the easing of industrial and commercial activity. The rise in levels is aided by rainfall recharging the reserves, but it points to the acute stress we impose on aquifers.
Most remarkably, the nation-wide lockdown has considerably reduced municipal solid waste (MSW) generation. Pune’s daily tonnage of MSW has fallen by 29 per cent, while Chennai’s and Nagpur’s have dropped by 28 per cent and 25 per cent, respectively. Even in cities like Delhi and Mumbai, one can expect a similar drop owing to a shift in consumer demand and behavioral changes towards sustainable consumption.
The point is that even though normal life has come to a standstill, the lockdown has given us a rare opportunity to step back and assess our impact on the environment. We are witnessing clean air, water and liveable cities that we have demanded for so long precisely because we have been shut away. Thus, before we resume life as usual, commitment to the following practices is necessary to ensure that we instil principles of sustainable development in our social behaviour and public policy making.
Opportunity to not waste
India’s inefficient use of resources, poor state of waste segregation and near-complete dependence on centralised waste collection has mothballed into our cities throwing out mountains of refuse every year.
For instance, the solid waste from Delhi, Mumbai, Kolkata and Chennai put together tips the scales at around 29,000 tonnes per day, while India annually puts out about 55 million tonnes of MSW. Not only is it a logistical challenge to collect and process, but the waste dumps leach toxins into the soil and groundwater that are then fed back through the food chain.
The decomposition of organic waste also releases methane (CH4) and nitrous oxide (NO2) into the air, which are greenhouse gas.
A particularly useful solution lies in industries, hotels and recreational facilities switching to decentralised waste management. These sectors should scale down dependence on centralised waste treatment systems as part of their “zero waste” commitments by employing nature-based solutions (NBSs), that follow sustainable practices.
NBSs allow for an eco-friendly, site-specific approach for liquid waste, while also reducing the cost burden of industrial-scale waste treatment. For example, large hotels and resorts can effectively pioneer solutions such as constructed wetlands (CWs) for water recycling, which would also add to the local landscape’s aesthetics.
Waste is wealth. Source-segregated solid waste that is bio-composted, vermin-composted or anaerobically digested, based on bio-recycling methods, would be a cost-effective means of generating organic manure and megawatts of bioenergy, respectively. Successfully running biogas programs across our villages and nearly 100MW worth of biomethanation plants across Delhi, Chennai, Jabalpur and Hyderabad are proof of their suitability for Indian conditions. A mandatory drive for household-level waste segregation across urban India would thus be an essential first step.
For the water-heavy industries of pharmaceuticals, paper, food and beverage, adopting best practices in minimising water consumption would progress them towards Zero Liquid Discharge (ZLD). Bio-treatment of industrial effluents such as chemicals, detergents and toxic sludge are also well within our capacities, and compliance needs to be mandated to keep our rivers clean.
Manufacturing with bio-composites
Bio-composites are an exciting new solution to the ever-increasing demand for industrial raw materials. These are structures that have naturally occurring minerals woven together into a matrix of natural fibres, such as cellulose and lignin.
Because of their strength, lower weight and recyclability, bio-composite products are being used as environmentally superior alternatives to traditional raw materials such as wood and plastic. For instance, starch-based clay nanocomposites can be a possible alternative for food packaging, while certain bio-composites are used to supplement high-strength carbon fibre structures for industrial applications.
Making it a long-lasting lesson
Just as an occasional fast helps our bodies purge out toxins and regenerate, the Covid-19 emergency and the lockdown – despite the hardships they have caused – have scrubbed our environment clean and handed us the opportunity for a restart.
Yet, if conscious action is not made to adopt nature-based solutions, the country will soon be back to pre-lockdown levels of pollution and possibly be vulnerable to the next crisis. Therefore, going forward it’s important that we adopt behavioural changes towards a less resource-intensive lifestyle, and our industries pay as much attention to long-term sustenance as to economic growth for a truly successful recovery.
(S N Tripathi is professor and head, Department of Civil Engineering, Centre of Environmental Science and Engineering, IIT Kanpur. Subrata Hait is associate professor at IIT Patna. The opinion expressed is personal)
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