Toxic foam resurfaces in Yamuna as Delhi-NCR air quality deteriorates sharply

Toxic foam has reappeared on the Yamuna River as air quality across Delhi and the National Capital Region slides into unhealthy levels, signalling the onset of the region's annual winter pollution crisis. The deterioration in air quality prompted the Commission for Air Quality Management (CAQM) to invoke Stage 1 of the Graded Response Action Plan (GRAP) across Delhi-NCR on October 21 to implement curbs on air pollution.

The GRAP is a set of measures designed to progressively restrict activities that contribute to air pollution as conditions worsen. Stage 1 typically includes advisory measures such as discouraging use of diesel generators, promoting public transport, and heightening public awareness about pollution risks.

The reappearance of foam on the Yamuna, a recurring problem during winter months, is attributed to low water flow and high pollutant concentrations in the river. The toxic foam, often composed of industrial effluents and household waste, poses health risks to residents and exacerbates the region's air quality challenges.

During the winter season, Delhi-NCR regularly experiences severe air pollution due to a combination of meteorological factors including temperature inversions, reduced wind speed, and increased moisture retention. This year's activation of GRAP Stage 1 marks the beginning of what authorities expect could be a challenging pollution season for the region.