Weather conditions for the dispersal of pollutants are more adverse this year compared to last year, officials from the Central Pollution Control Board (CPCB) said at a technical briefing on air pollution on Friday, suggesting that the Pollution levels could be relatively higher this year.
Last year in September and October, there were seven days of rain that brought about 121mm of rain compared to just three days of rain this year in the same period that brought only 21mm of rain. The average ventilation index in the same period this year is 1,389 m2 / s but the minimum recorded was only 636 m2 / s. A ventilation rate of more than 6,000 m2 / s is considered favorable for the dispersion of pollutants, according to CPCB officials.
Prashant Gargava, Member Secretary, CPCB, said that the harvesting of the kharif crop and the burning of stubble has started earlier than normal this year. He added that the peak of stubble fires may not coincide with the worst weather conditions this year.
Last year, the contribution of stubble to Delhi’s air pollution peaked on October 31 when it was 44%. Diwali was celebrated on October 27 of last year.
“This year, because the stubble fires have started relatively early, we expect the maximum contribution from the fires to decrease when the minimum temperature begins to drop significantly and before Diwali,” Gargava said.
Diwali will be celebrated on November 14 this year.
Another development, which could mean a smaller contribution from stubble fires this year, is that the area under non-basmati rice (which leaves stubble that needs to be removed) has been reduced in both Haryana and Punjab this year. In Punjab, the area under rice fields other than basmati has decreased from 22.91 lakh ha to 20.76 lakh ha this year. In Haryana, the area has been reduced from 6.48 lakh ha to just 4.27 lakh ha.
“I have been informed that farmland over 1 lakh ha has been changed for rice this year, which is a very important development,” added Shiv Das Meena, President of CPCB.
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