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Updated: Oct 14, 2019 00:16 IST

Delhi residents were greeted with a hazy Sunday morning as air quality index (AQI) continued its plunge into the ‘poor’ category even as meteorological scientists said the situation is likely to worsen in the coming days due to low wind speed and crop residue burning in Haryana and Punjab.

Scientists at India Meteorological Department (IMD) said conditions are favourable for the complete withdrawal of the southwest monsoon in the next few days, which would change the weather pattern across northwest India bringing in a slight nip in the air along with dry weather and also weeks of poor air quality. “We have already started recording lower minimum temperatures and relatively calm atmospheric conditions,” said VK Soni, senior scientist at IMD.

The overall AQI in Delhi on Sunday touched the 270 mark, which falls in the ‘poor’ category. Several parts of the city reported AQI in the ‘very poor’ zone, according to Central Pollution Control Board (CPCB) data. The continued spike in pollution levels over the past week has given Delhi-NCR its worst spell of pollution in three months.

An AQI between 0 and 50 is considered ‘good’, 51 and 100 ‘satisfactory’, 101 and 200 ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’, and 401 and 500 ‘severe’.

Experts, however, said relief is not on the horizon and the situation will likely become worse in the coming days. “We are expecting air to be in the ‘very poor’ or in the upper end of ‘poor’ AQI on October 13 and 14 when wind direction is north-westerly and wind speed is less than 10kmph,” said Soni.

The increasing number of crop stubble burning cases in the neighbouring states of Punjab and Haryana are also adding to the problem. “Due to monsoon withdrawal, the winds are not strong enough to blow away (these) pollutants from Delhi. The wind direction has also changed from east to northwest, which means that all the pollutants from the burning activity in Haryana and Punjab are coming to Delhi,” an IMD statement read.

There will, however, be a breather from October 15 to October 19 when wind direction changes briefly to ‘easterly’ and pollution laden winds from Punjab and Haryana will not be blowing towards Delhi, he said.

The Centre-run System of Air Quality and Weather Forecasting and Research (Safar) said smoke from stubble burning will make up 6% of Delhi’s pollution by October 15.

From October 1 to October 10, stubble fires were lowest in eight years according to an analysis by Hiren Jethva, research scientist, Universities Space Research Association (USRA) at Nasa’s Goddard Space Flight Centre. But this is mainly because of an extended monsoon and consequent delay in post-monsoon harvest, he had said.

Meanwhile, IMD scientists said conditions are favourable for complete withdrawal of monsoon in the next couple of days and commencement of northeast monsoon in Peninsular India around October 20.

According to IMD’s forecast, between October 10 and 16 minimum temperatures are likely to be normal to below normal over most parts of the country except Gujarat, Karnataka and Chhattisgarh, where it is likely to be slightly above normal.

After that, minimum temperatures are likely to increase over south Peninsular and adjoining central India and likely to be below normal over rest of the country. “Conditions are very likely to become favourable for a complete withdrawal of southwest monsoon from the country and commencement of northeast monsoon rainfall over southeast India during October 17 and October 23,” the forecast added.

Between October 1 and October 9 before the southwest monsoon started withdrawing from northwest India, the region recorded 103% more post-monsoon rainfall compared to normal. According to IMD Pune, the northeast monsoon season has started with a deficiency of 52% and 32% in Tamil Nadu and Kerala respectively in the first week of October while Karnataka and Rayalseema have an excess of 53 and 21% respectively.

“Parts of Andhra Pradesh and Telangana are already receiving rains which will merge with northeast monsoon later. Around 60% of the annual rain received in Tamil Nadu is during the northeast monsoon period (October to December). It’s very difficult to say immediately if northeast monsoon rain will be normal,” said Mahesh Palawat, vice president (climate change and meteorology), Skymet Weather, a private weather forecasting agency.

He added that a “gradual spike in air pollution levels is expected after October 20 when weather pattern would have changed, stubble burning would be at its peak and it will be nearing Diwali festivities.”