America's space agency NASA (National Aeronautics and Space Administration) has revealed in the findings of a study conducted after Diwali that the real cause of pollution in Delhi is not crackers, but stubble burning in neighbouring states.
As of November 16, the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor detected more than 74,000 hotspots in Punjab, the NASA report said. This number is roughly the same as the 85,000 hotspots detected by the sensor in 2016.
On November 11, NASA noted that stubble burning in Punjab and Haryana caused a sharp decline in air quality in northwestern India. NASA found that due to the increase in the speed of stubble burning, fire activity increased in the month of November. "VIIRS aboard the Suomi NPP satellite on November 11, 2021, observed huge plumes of smoke emanating from the fires in Punjab and Haryana, moving towards Delhi, one of the most densely populated cities in India," it said. The space agency said the fires in Pakistan also contributed to the smoke.
According to Pawan Gupta, who works at NASA's Marshall Space Flight Center, at least 22 million people were affected by the smoke produced by stubble burning on November 11 alone. NASA reported that sensors in India's national capital had recorded PM 2.5 and PM 10 levels above 400 micrograms per cubic meter on several occasions in November, which is higher than the WHO recommended level of 15 micrograms per cubic metre.
Using the Moderate Resolution Imaging Spectroradiometer on NASA's Aqua satellite, scientist Hiren Jethwa concluded, "Earlier this summer we saw the largest differential vegetation index (NDVI) on record in more than 20 years." Based on that, I predicted it would be one of the most active fire seasons ever, and that's exactly what happened. He said that the time of stubble burning would be a few more weeks but Aqua Modis has already detected more than 17,000 hotspots in Punjab and Haryana. This means that it will increase even more.