Explainer: What is air pollution in Delhi? How is it measured?

Delhi and its surrounding areas are under a thick blanket of smog since November 13, 2024 and the highest AQI of 493 was recorded on November 18, 2024. At least four places in Delhi had touched 500, with many others hovering between 490-500. With visibility down to 150 metres due to the thick smog, around 14 flights were diverted to airports in neighbouring states. After days of severe plus conditions, Delhi’s air quality showed slight improvement on Thursday (Novmeber 21, 2024). While AQI in some areas remained severe, some areas AQI recorded slight improvement.

Supreme Court monitoring the situation:

The Supreme court which is hearing the plea seeking directions to curb the pollution in the capital, stated that it would not allow scaling down of the preventive measures under stage-4, even if ADI goes below 450.

Cloud seeding efforts:

The Delhi government has been even considering cloud seeding as a measure to combat this problem. Speaking to the news media, Delhi Environment Minister Gopal Rai said the city’s government was ready to go ahead with an emergency plan to stimulate artificial rain to clear the smog but blamed the federal government for delaying approvals.

The Delhi government has requested the Centre to allow cloud seeding- a method used to induce artificial rain to combat air pollution. According to experts, artificial rain can wash away pollutants from the atmosphere and help improve the air quality. IIT Kanpur has proposed the cloud seeding project to the Delhi government but the implementation of cloud seeding in Delhi is facing several challenges. The current weather patterns in Delhi may not be conducive to be successful with cloud seeding operations. IIT Kanpur mentioned that the permissions for cloud seeding as pending.

Let’s understand what is AQI

Air Quality Index (AQI) measures the concentration of five common air pollutants: ground-level Ozone, particle pollution, Carbon monoxide, Sulphur dioxide, and Nitrogen dioxide. AQI is number between 0-500 that indicates how clean or polluted the air is, High AQI value means greater air pollution and greater health concern. 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’, 401 and 450 ‘severe’ and above 450 ‘severe plus’. AQI measures the levels of particulate matter, also called PM 2.5, in the air. These tiny particles can enter the lungs and cause a host of diseases.

Health Emergency

Local Circles, an online community platform, took responses from over 21,000 residents across Delhi, Gurugram, Noida, Faridabad and Ghaziabad, with 63 % of respondents comprising men and 37 per cent women. The survey also states that 27 % of families have acquired air purifiers as a protective measure.

many cases of youngsters reporting pneumonia without typical signs of infection. Usually, it begins with flu-like symptoms — fever and chest congestion. If the symptoms persist longer and become more stubborn, then chances are the patient is suffering from what is called “walking pneumonia.” The symptoms are Chest pain, fever less than 101 degree Fahrenheit, sore throat, weakness, fatigue, rash, chills, cough, sneezing and headache.

What are the causes of Air pollution in Delhi?

Delhi’s air pollution has several sources, including industries, waste disposal, stubble burning, vehicular emissions etc. A study by the Centre for Science and Environment reveals that during October 12 – Novmeber 3, 2024, vehicular emissions were the largest contributor to Delhi’s air pollution. This accounts for 51.5 % of city’s pollution. Pollution from neighboring distircts amount to 34.9 %, farm fires contribute to 8.19% and dust particles make 3.7% of the total air pollution in Delhi.