The India Meteorological Department (IMD) has forecast cloudy skies and light rain and thundershowers in parts of Delhi-National Capital Region (NCR) on Thursday which, along with a slightly higher wind speed, will improve air quality marginally until Friday.
It rarely rains in October in the capital because the south-west monsoon usually withdraws completely by this time. There was no rain in October last year. There was 2 mm rain in 2016; 0.4 mm in 2015; and 2.22 mm in 2014. October 2013 was unusually wet, with Delhi getting 72.7 mm of rainfall.
The high humidity due to outflow of the Luban cyclone in the Arabian Sea is bringing moisture to the region, with a cyclonic circulation over Rajasthan due to a western disturbance creating favourable conditions for clouds and light thundershowers in parts of Delhi-NCR.
The relative humidity on October 9 was about 63% and maximum humidity till 8.30 am on Wednesday was 98%. According to IMD meteorologists, humidity should be less than 50% at this time of the year. The IMD has also forecast thunderstorms accompanied by hailstorms in parts of Punjab, northern parts of Haryana, Chandigarh and western Uttar Pradesh.
“We are seeing medium to high clouds in Rajasthan, Haryana, Delhi and parts of Uttar Pradesh. Moisture is also higher than normal. This is mainly because of the moisture from the cyclone over Arabian Sea and a cyclonic circulation over Rajasthan induced by a western disturbance. These conditions may bring light rain to the capital. But after Thursday, it will become dry again,” said BP Yadav, deputy director general, IMD.
Though there is a slight dip in minimum temperature compared to September, the minimum temperature on Wednesday was 2 degrees above normal at 23 degrees C.
The dry winter chill will set in Delhi in the first week of November, when the maximum daytime temperature will also fall. “We are already seeing a slight dip in minimum temperature, especially during early morning and night but daytime temperature is usually higher in October compared to September because of a clearer sky and direct sunlight. Daytime temperature will start falling from the first week of November,” Yadav said.
The forecast for Thursday is a partly cloudy sky with a possibility of light thundershowers. The maximum temperature is likely to be around 34 degrees C, and the minimum around 23 degrees C, according to the Regional Meteorological Centre in Delhi.
Air quality in Delhi will improve marginally on Thursday and Friday because of rain and a slightly higher wind speed. “The forecast we have from IMD says conditions are favourable for dispersal of pollutants on October 11 and 12. The wind speed at about 15 km per hour will (help/aid?) dispersal. We haven’t got the forecast for later,” said VK Shukla, in-charge of the air lab at the Central Pollution Control Board (CPCB).
Farm fires have led to a dip in air quality, with 400 fires reported in Punjab and 328 in Haryana till October 9, according to a CPCB official. “The data we have shows fire incidents are lower this year compared to last year during the same period. An analysis of fire incidents is being compiled,” he said.
Delhi’s air quality has been mostly in the “poor” category since October 4. On Wednesday, the average PM 2.5 (fine, respirable pollution particles mainly from combustion sources) concentration was about 102 micrograms per cubic metres against a safe standard of 60 micrograms per cubic metres, PM 10 (coarse pollution particles like dust) concentration was about 271 micrograms per cubic metres against a safe standard of 100 micrograms per cubic metres.
Farmers, government officials and scientists met on Wednesday in Chandigarh to discuss the stubble burning problem responsible for impairing air quality in northern India at this time of the year. Punjab’s chief principal secretary, Suresh Kumar, said, “Punjab’s farmers are the worst hit despite, and due to, the policies and schemes of the green revolution. Penalising and arresting farmers without addressing their concerns at the ground level is not something a democratically elected government should be encouraging.”
He added: “ There is a need for a variety of viable choices to be made available to the farmer. Some of the schemes that the government has initiated include in situ management, which is part of the solution.”
According to a statement by Climate Trends, an organisation focusing on communication of environmental issues, which organised the meeting. CPCB officials said air pollution levels may pick up if fires in Punjab and Haryana intensify and coincide with the festivities next week and transition of meteorological conditions to the arrival of winter.
First Published: Oct 10, 2018 23:00 IST