Delhi Sees Second-Worst December Day With Air Quality Index At 461

The AQI in Delhi climbed to 461 on Sunday and marked the city's most polluted day this winter and the second-worst December air quality day on record, as weak winds and low temperatures trapped pollutants close to the surface.

The air quality monitoring station at Wazirpur recorded the maximum possible Air Quality Index (AQI) value of 500 during the day, beyond which the Central Pollution Control Board (CPCB) does not register data.

By 4 pm, 38 of Delhi's 39 active air quality monitoring stations reported 'severe' pollution levels, according to the CPCB's Sameer app, with only Shadipur remaining in the ‘very poor' category.

Rohini also touched 500 during the day, while Ashok Vihar, Jahangirpuri and Mundka recorded AQI readings of 499.

Dense smog engulfed the national capital, and the AQI rose from 432 a day earlier to set the record -- since the AQI monitoring system was introduced in April 2015.

The only instance of higher pollution in the month was on December 21, 2017, when the average AQI reached 469.

Although wind speeds are expected to increase after noon on Monday, forecasts suggest that any improvement in air quality will be gradual.

As per the Central Pollution Control Board (CPCB), an AQI between zero 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'.

Health experts warned of serious public health risks due to the prolonged exposure to hazardous air.

Shila Yadav, a health expert, said that with the AQI hovering between 300 and 400 and even breaching the 450 mark, people should avoid outdoor walking or exercise, particularly in the morning hours.

She said while physical activity should not be stopped, it must be shifted indoors, as exposure to polluted air can cause fine particulate matter such as PM2.5 to penetrate deep into the lungs.

Yadav advised people to step out only when necessary, preferably later in the day when sunlight improves dispersion, and said wearing masks was essential for those who must go out for work.

She also cautioned against strenuous activities that involve heavy breathing and stressed the importance of a healthy diet, adequate hydration and consumption of seasonal fruits to help the body flush out toxins.

The Commission for Air Quality Management (CAQM) on Saturday invoked the strictest measures (Stage IV) under its air pollution control plan, Graded Response Action Plan (GRAP), including a ban on all construction and demolition activities in Delhi-NCR after pollution levels rose sharply amid unfavourable meteorological conditions.

The Sub-Committee on GRAP decided to invoke Stage III of the GRAP earlier on Saturday across the entire NCR with immediate effect as air quality continued to worsen.

On the weather front, the minimum temperature settled at 8.2 degrees Celsius on Sunday, 0.4 notch below the season's average, and the maximum temperature recorded at 24 degrees Celsius.

The relative humidity was 87 per cent at 5.30 pm, the India Meteorological Department said.

Environmentalist Bhavreen Khandari said the current actions are reactive, emphasising that long-term improvement depends on present systemic policy decisions.

Pointing to massive construction, she stressed the need to address resource and staffing deficiencies in government bodies.

The weather department has forecast moderate fog for Monday, with maximum and minimum temperatures expected to hover around 23 degrees Celsius and 8 degrees Celsius, respectively. 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)