Delhi AQI Nears 400, Enters Severe Category As Air Pollution Worsens Ahead Of Diwali

Delhi's air pollution remained high on Thursday morning, with the Air Quality Index (AQI) near India Gate reaching 399, just two points below the 'severe' threshold of 401, while Anand Vihar recorded 296 in the 'poor' category, ANI reported, citing Central Pollution Control Board (CPCB) data.

Nauroji Nagar Ring Road recorded an AQI of 416, while the reading near AIIMS stood at 402, with both locations falling in the 'severe' category, according to CPCB data.

Delhi's overall AQI settled at 377 on Wednesday, its highest since January 20, when it was recorded at 378, making it the worst reading in 288 days. With Diwali approaching, the Air Quality Early Warning System has forecast that pollution levels could enter the 'severe' category on November 6 and 7. The worsening pollution has also raised concerns over its wider health consequences, with Dr Ambrish Mithal, Group Chairman and Head of Endocrinology and Diabetology at Max Healthcare, warning of its impact on diabetes and cardiovascular health.

Stubble Burning And Transport Contribute To Delhi's Pollution

According to a PTI report, 22 of Delhi's 59 monitoring stations recorded 'severe' air quality on Wednesday, while 32 were in the 'very poor' category and five recorded 'poor' air quality. IIT Delhi registered the highest AQI at 458, followed by Jahangirpuri and Punjabi Bagh at 448 each. Mundka recorded an AQI of 439.

The Air Quality Early Warning System forecast that Delhi's air quality would remain in the 'very poor' category on Thursday before deteriorating to the 'severe' category on November 6 and 7.

PM10 emerged as the dominant pollutant on Wednesday, replacing PM2.5, which had remained dominant over the preceding three days. PM10 refers to particulate matter measuring up to 10 micrometres in diameter and includes both fine and coarser particles. Road and construction dust are among its sources.

The pollution-source estimates also pointed to contributions from both local emissions and farm fires in neighbouring states. According to the Decision Support System (DSS), stubble burning accounted for 20.2 per cent of Delhi's pollution on Wednesday, while transport emissions contributed 15.5 per cent. Residential sources accounted for 3.8 per cent, industries 2.9 per cent, construction 2.2 per cent, waste burning 1.3 per cent and road dust 1.1 per cent. Other sectors contributed one per cent.

Among the neighbouring NCR districts contributing to Delhi's pollution, Ghaziabad accounted for seven per cent, followed by Rohtak at 3.8 per cent, Gurugram at 2.7 per cent, Sonipat at 2.2 per cent, Jind at 1.8 per cent and Bhiwani at 1.3 per cent. Other sources accounted for 28.5 per cent.

Separately, satellite data recorded 467 farm fires across six states on November 4, according to the ICAR-Indian Agricultural Research Institute (ICAR-IARI). Madhya Pradesh recorded 157, Punjab 151, Rajasthan 111, Uttar Pradesh 33, Haryana 10 and Uttarakhand five. No farm fires were detected in Delhi.

The CREAMS Laboratory of the ICAR-Indian Agricultural Research Institute reported that 4,800 residue-burning events had been detected across seven states and Union Territories, including Delhi, between September 15 and November 4. These included 2,347 in Punjab, 949 in Rajasthan, 865 in Madhya Pradesh, 392 in Uttar Pradesh, 183 in Uttarakhand, 62 in Haryana and two in Delhi.

Air Pollution Linked To Diabetes And Cardiovascular Risks

Speaking about the health effects of air pollution, Mithal said Indian studies had shown a direct impact of PM2.5 exposure on the prevalence of diabetes and high blood pressure.

"Even one month exposure to a PM 2.5 can raise your blood sugar and over the years the risk of diabetes can go up by 22%. It's a very important contributor to our diabetes risk," Mithal told ANI.

A 2023 study published in BMJ Open Diabetes Research & Care, which examined participants in Delhi and Chennai, found that a 10 microgram per cubic metre increase in annual average PM2.5 exposure was associated with a 22 per cent higher risk of developing type 2 diabetes.

"India is a diabetes capital of the world," Mithal said, adding that air pollution was an important contributor to the country's diabetes risk.

Explaining how particulate matter affects the body, he said the particles contain nitrates, sulphates, heavy metals and carbon. When inhaled, these tiny particles enter the lungs and are absorbed into the bloodstream, where they can damage arterial walls and contribute to hypertension and vascular disease.

"They also reach the pancreas and they have some impact on insulin secretion, exciting inflammation inside the pancreas and also they have an impact on insulin action. So insulin resistance also happens," he said.