Delhi’s air quality remained in the very poor category on Thursday as the city was on the brink of a public health emergency with an air quality index (AQI) of 364 on Wednesday being the worst this season. An overall AQI of 351 (very poor) was recorded at 8am. At 8:05am, the air quality was severe at places such as Anand Vihar (413), Bawana (401), Mundka (420), and Punjabi Bagh (416). On Wednesday, AQI in the same zone was recorded in parts of the Capital including Mundka (417), Anand Vihar (416), Wazirpur (409) and Punjabi Bagh (408). Bawana and Rohini reported brief spells of severe air on Wednesday afternoon.
The pollution levels were likely to worsen over the next few weeks despite a series of mitigation measures. The haze enveloping Delhi was largely because of local pollutants concentrating in the air due to still winds and plunging mercury. The contribution of farm fires in neighbouring states was still low because of a favourable wind direction.
Delhi’s PM2.5 (ultra-fine particulate pollutants) levels on Wednesday due to farm fires were around 13%, according to the estimates of the Union earth sciences ministry’s Decision Support System (DSS). The city’s transport sector contributed 11.4% while 10.4% came from neighbouring Gautam Budh Nagar. DSS does not measure pollutants in real time.
Farm fires in Punjab and Haryana have increased over the past week, but they were not so far at levels they tend to be around this time of year. Punjab and Haryana reported 1,556 farm fires on Tuesday, nearly triple the number a week ago (442). But they were lower than 1,769 on October 31 last year and 3,137 in 2021. Year-on-year data on stubble fires is not always comparable due to differences in cropping and harvest patterns.
A southeasterly current like the one the Capital is experiencing right now takes most of the farm smoke towards Rajasthan and across the border. A northwesterly current brings it towards the city.
Bad air affects most elderly, children and those with pre-existing conditions or impaired immunity. The pollution levels as high as Delhi is experiencing also threaten healthy adults. Polluted air can cause bronchitis, asthma, anaemia and acute respiratory infections, apart from nausea.
A 2018 World Health Organisation (WHO) study found pregnant women exposed to polluted air are more likely to give birth prematurely and have small, low birth-weight children. Air pollution impacts neurodevelopment and cognitive ability and can trigger childhood cancer. Children exposed to high levels of air pollution are likely to be at greater risk for chronic diseases such as cardiovascular disease later in life, according to WHO.
An upsurge in the number of patients with severe coughs, allergies and respiratory illnesses has been reported with the spike in pollution.
Delhi’s sky was expected to be clear with some fog on Thursday and Friday. On Thursday, the predominant surface wind from east and northwest was likely to be calm in the morning.