The major summer months in India—April, May and June—are unbearably hot in most parts of the country. India recently dealt with the third-hottest April the country has seen over the past 122 years, according to government officials, and March was the hottest ever recorded. We have already seen unbearably hot days in the month of May as well. While such heat waves are expected to become more common because of climate change, they are often due to multiple specific factors, including ocean events in the Pacific and Atlantic oceans. Globally, summer in 2022 will be under the continued influence of the El Niño, which will create a hotter than normal and drier summer in many parts of the world. It is also dreaded that the average temperature of the next five years will be higher than the past five years, as the climate crisis intensifies. 

This month’s cover story ‘Microplastics in Ganga River’ delves into two recent studies that have revealed the high prevalence of microplastics in the Ganga River basin, and pointed to the risks involved to freshwater biodiversity in the region. The first of these studies, “Quantitative Analysis of Microplastics along River Ganga” by Toxics Links, was done by examining the waters of the Ganga River off Haridwar, Kanpur and Varanasi at several points in the respective cities, and documenting the kinds of microplastics present in the waters. The second study, “Risk Assessment of Plastic Pollution to Migratory Species in the Mekong and Ganga River Basins” done for the United Nations Environment Programme (UNEP) and the Convention on Conservation of Migratory Species of Wild Animals (CMS) examined the waters at several points of the Mekong and Ganga basins.

Currently, wastewater treatment plants are the only barriers to check microplastics from flowing into riverine waters, and thence, into the sea. Although not all microplastics can be removed through water treatment, studies show that primary and secondary treatment of wastewater can remove a large part of microplastics, and prevent them from polluting riverine waters. Studies show that 78–98 per cent of the microplastics get removed in the primary stage, while an additional 7–20 per cent can be removed at the secondary stage. Since tertiary treatment varies from plant to plant, one cannot determine the exact amount that is removed. However, every wastewater treatment removes a large amount of microplastics as sludge, although there is no waste treatment plant that can yet remove microplastics completely.  It is, hence, imperative that there are ample water treatment plants to treat domestic and industrial sewage along the course of the Ganga River. For complete removal of microplastics in the near future, further research into new and improved methods of treatment will be essential.