Every November, satellites detect large clouds of smoke and increased fire activity in northwest India as farmers burn extra paddy straw after rice harvesting. Many farmers, especially in the states of Punjab and Haryana, use fire as a quick and inexpensive way to clean and fertilize fields before planting winter wheat crops. However, the wave of fires in the heart of the densely populated Indogangetic tasango often causes a sharp deterioration in air quality in November and December.
Although prolonged monsoon rains this year kept fire activity low for a few weeks longer than usual, satellites noticed increased fire activity in November as the rate of burning accelerated. Of 11.11.2021 Visible Infrared Imaging Radiometer Suite (VIIRS) is Satellite of the Finnish nuclear power plant acquired this naturally colored image of a river of smoke flowing from the fires of Punjab and Haryana towards Delhi, one of the most populous cities in India. Use the image comparison slider to see the locations hotspots VIIRS spotted that afternoon. The fires in northern Pakistan are also likely to have caused some of the smoke.
“Looking at the size of the flood on November 11 and the population density of this area, I would say that a conservative estimate puts at least 22 million people affected by smoke that day,” he said. Pawan Gupta, A researcher at the Universities Space Research Association (USRA) at NASA’s Marshall Space Flight Center.
As in previous years, sensors in Delhi and elsewhere in North India have recorded soaring levels of air pollution. Sensors in the metropolitan area – including one at the U.S. Embassy– recorded concentrations fine particles (PM2.5) and coarse particles (PM10) well above 400 micrograms per cubic meter on several occasions in November. Because the particles are associated with a number of respiratory, cardiovascular and other diseases health problems, World Health Organization instructions we recommend a 24-hour average PM2.5 concentrations are kept below 15 micrograms per cubic meter. High levels of pollution led partial locks, school closures and construction interruptions in Delhi and other cities.
The smoke from the crops is not the only reason for the fog in the sky. Dust streams sometimes arrive west of the Thari Desert – as happened on November 12, 2021 (see photo below). A number of other man-made sources of air pollution in cities, including motor vehicle fumes, industrial and construction activities, fireworks and fires related to heating and cooking, also produce particles and other pollutants.
Geography and weather also exacerbate air quality problems in the area. Temperature inversions are common in November and December when air flows out of the Tibetan Plateau and mixes with smoky air from the Indogangetic Plateau. The inversion can act as a deck, with warm air binding the pollutants close to the surface and helping to pollute the pollutants between the mountains of the northern Himalayas and the mountains of Vindhya in the south.
Hiren Jethva, A scientist at the USRA (University Space Research Association) at NASA’s Goddard Space Flight Center, uses “greening” or Normalized Difference Vegetation Index (NDVI) measurements anticipate fire operations every year. The information he uses is from Medium resolution imaging spectroradiometer (MODIS) at NASA Aqua satellite.
“Earlier in the summer, we saw one of the highest NDVI values in a record of more than 20 years. On that basis predicted this would be one of the most active fires ever, and that is exactly what we have seen, ”Jethva said. “We still have a few weeks left to burn, but Aqua MODIS has already detected more than 17,000 hotspots In Punjab and Haryana – that’s how it is the most active fire season “Aqua MODIS started collecting data in 2002.
The Visible Infrared Imaging Radiometer Suite The (VIIRS) sensor makes similar measurements, but it can detect many small and low temperature hotspots that MODIS ignores. On November 16, VIIRS had noticed more than 74,000 hotspots in Punjab. “It’s close to the 85,000 that the sensor detected in 2016, the most active year of the VIIRS record,” Gupta said.
Although the total number of fires has remained consistently high in Punjab, satellite data show that campaigns by farmers to clear fields without fire have proved more successful in Haryana. “During the nine-year VIIRS observation, we don’t see a big trend in Punjab. However, in Haryana, we saw a 45 percent drop in total fires in 2020 compared to the 2012-2019 average,” Gupta added. “But fires appear to be at the higher end In Haryana again this year. “