Overnight Rain Brings Glimmer Of Hope To Delhi's Air Quality Amidst Pollution Woes

The long-standing battle against hazardous pollution in the national capital received a much-needed respite on Friday morning, as overnight rain washed away some of the toxic particles that have plagued the city for over a week. The visible improvement in Delhi's air quality raised hopes, with experts anticipating a reduction in the Air Quality Index (AQI) as the day progresses.

At 7 am, Delhi's AQI registered at 408, a noticeable improvement from the 437 recorded at 4 pm on Thursday. The change in fortune comes on the heels of the India Meteorological Department's (IMD) prediction of a slight improvement in air quality, thanks to favourable meteorological conditions and the recent light rain.

IMD officials have attributed the positive shift to a change in wind direction, as a fresh western disturbance affecting northwest India steers winds from the northwest to the southeast. This shift will help reduce the contribution of smoke from stubble burning, a major source of air pollution in the region.

The data from the Decision Support System, a numerical model-based framework, revealed that stubble burning in neighbouring states, especially Punjab and Haryana, contributed to 38% of Delhi's air pollution on Wednesday, a figure that dropped to 33% on Thursday and is expected to further decrease to 16% on Friday.

Transport also remains a significant contributor to the city's foul air, accounting for 12 to 14% of the pollution problem.

In response to the deteriorating air quality, the Delhi government is planning to induce artificial rain on November 20-21 through cloud seeding. A proposal to this effect will be submitted to the Supreme Court, which has been hearing petitions on the air pollution issue.

The government has also taken measures to address the problem at its source. Delhi Environment Minister Gopal Rai announced a ban on the entry of app-based taxis into the capital, in line with the Supreme Court's orders. The city is also gearing up for the implementation of the odd-even car-rationing scheme, which will come into effect after the court reviews its effectiveness and issues an order. This matter will be heard by the court on Friday.

However, on Tuesday, the Supreme Court questioned the effectiveness of the car-rationing scheme, referring to it as "all optics." Anticipating a further decline in air quality post-Diwali, Mr Rai announced that the odd-even scheme will be enforced between November 13 and November 20.

Medical experts have issued warnings about the health risks associated with breathing in the polluted air of Delhi. They likened the effects to smoking approximately 10 cigarettes a day and highlighted that prolonged exposure to high pollution levels can lead to respiratory problems like asthma, bronchitis, chronic obstructive pulmonary disease (COPD), and significantly increase the risk of cardiovascular disease.

To address the escalating crisis, stringent restrictions mandated under the final stage of the Centre's air pollution control plan for Delhi-NCR, the Graded Response Action Plan (GRAP), have been put into effect. Stage IV of the GRAP includes a ban on all construction work and the entry of polluting trucks into Delhi. These restrictions were imposed when the air quality reached "severe plus" levels (AQI above 450).

The GRAP categorizes actions into four stages: Stage I (Poor), Stage II (Very Poor), Stage III (Severe), and Stage IV (Severe Plus), depending on the AQI.

Unfavourable meteorological conditions, combined with vehicular emissions, paddy-straw burning, firecrackers, and other local pollution sources, contribute to hazardous air quality levels in Delhi-NCR during winter. According to the Delhi Pollution Control Committee (DPCC), the capital experienced peak pollution from November 1 to November 15, coinciding with a surge in stubble-burning incidents in Punjab and Haryana.

Delhi's air quality has consistently ranked among the worst in the world's capital cities, with a recent report from the Energy Policy Institute at the University of Chicago (EPIC) indicating that air pollution is shortening lives by almost 12 years in Delhi. The recent overnight rain provides a glimmer of hope in the battle against this ongoing health crisis, but it remains a challenge that requires sustained efforts to combat.