With the onset of winters, Delhi Air pollution has started increasing. Delhi’s air quality remains in the ‘poor’ category with stubble burning causing a rise in pollution levels.
Air pollution in Delhi and the whole of the Indo Gangetic Plains is a complex phenomenon that is dependent on a variety of factors. The first and foremost is the input of pollutants, followed by weather and local conditions.
What is air pollution?
Read – Air Quality Index
Air pollution is the introduction into the atmosphere of chemicals, particulates, or biological materials that cause discomfort, disease, or death to humans, damage other living organisms, damage natural and built environment
What are air pollutants?
- A substance in the air that can be adverse to humans and the environment is known as an air pollutant. Pollutants are classified as primary and secondary
- A primary pollutant is an air pollutant emitted directly from a source. Like Volcanic eruptions or fires and carbon monoxide from vehicles.
- A secondary pollutant is not directly emitted as such, but forms when other pollutants (primary pollutants) react in the atmosphere. For ex: Tropospheric ozone or “bad ozone”, which is formed due to its interaction with other gases and substance.
Why Delhi air pollution rises in October?
- Northwesterly Winds: Month of October marks the withdrawal of Monsoon winds (South-West) from North India, leading to the arrival of North-Easterly winds.
- Monsoon winds carry Moisture and rainfall all over the country, whereas northwesterly winds carry dust from dust storms originating in Rajasthan and sometimes Pakistan and Afghanistan.
- As per the study conducted by scientists at the National Physical Laboratory, 72 per cent of Delhi’s wind in winters comes from the northwest, while the remaining 28 per cent comes from the Indo-Gangetic plains.
- One of such examples is a storm of 2017, originated from Iraq, Saudi Arabia and Kuwait that led to a drastic dip in Delhi’s air quality in a couple of days.
- Low-level inversion: Another factor is the temperature dip in the month of October. Low-temperature results in low-level inversion i.e. the layer that stops the upward movement of air from the layers below. It leads to the concentration of pollutants in the air at the lower heights.
- Wind speed: High wind speed in summers facilitates the faster movement of particulate matters in the air. As the wind speed decreases in winters, the air is not able to draw the pollutant away from a region.
- Landlocked Geography of Delhi: Geography of Delhi and the region around in the northern plains is landlocked. On the one hand source wind from North-West is already having pollutants, on the other, the Himalayas obstruct the escape route of air. Moreover, large buildings and other structures in Delhi also reduce airspeed.
- It is the reason that Chennai with the third-highest number of automobiles in India faces far less pollution in the city in comparison as coastal reason provides air with an effective route to enter and exit.
- Industrial chimney wastes: There are a number of industries which are source of pollution. The chief gases are SO2 and NO2. There are many food and fertilizers industries which emit acid vapours in air.
- Automobiles pollution: The Toxic vehicular exhausts are a source of considerable air pollution. In all the major cities of the country about 800 to 1000 tonnes of pollutants are being emitted into the air daily, of which 50% come from automobile exhausts. According to the IIT Kanpur study, 20 % of PM 2.5 in winters comes from vehicular pollution.
The exhaust produces many air pollutants including un-burnt hydrocarbons, CO, NOx and lead oxides.
- Dust pollution: Dust pollution originating from construction activities, raw road sides, from the neighbouring states, contributes to 56% of PM 10 and the PM2.5 load at 59 t/d, the top contributors being road 38 % of PM 2.5 concentration.
Paddy stubble burning:
- About the issue: Use of combine harvesters, has become a common practice after government law for delaying the sowing of paddy with an aim to conserve groundwater. It leaves farmers with very less time to get their fields ready. Moreover, paddy straw and stalks cannot be used to feed livestock, due to high silica content in them.
- In this hurry, farmers see burning of this stubble as a viable option. During peak stubble burning incidents, its contribution rose to 40%. As of now it is just 4%-5%, indicating the contribution of variety of other factors.
- The stubble burning season is around 45 days long. Air in Delhi, however, remains polluted till February.
- Government policies increasing stubble burning: One of such acts is Punjab Preservation of Subsoil Water Act, 2009, which is aimed at arresting Punjab’s falling groundwater tables. it banned farmers from transplanting rice in fields before June, so that they would not pump groundwater and rely more on the monsoon rains for their water supply.
- This allowed a window of barely 20 days for farmers to harvest paddy, clear fields and sow wheat for the next cycle.
Is this just a Delhi problem?
- Air pollution is not a problem of Delhi and its corporations alone but that of a big airshed around it that includes the National Capital Region (NCR). It includes Gurgaon, Faridabad, Ghaziabad, Noida, areas of Uttar Pradesh, Haryana and even Alwar in Rajasthan.
- An airshed, in geography, is defined as a region in which the atmosphere shares common features with respect to dispersion of pollutants; in other words, a region sharing a common flow of air.
Various initiatives to curb Delhi Air pollution
- SC appointed committee: one-man committee of Justice Madan B Lokur has been appointed to monitor stubble burning in Punjab, Haryana and Uttar Pradesh amid rising pollution in Delhi and its surrounding areas.
2. Graded response action plan: In pursuant with Supreme Court’s order in the M. C. Mehta vs. Union of India (2016) regarding air quality in National Capital Region of Delhi, the Graded Response Action Plan was notified by MoEFCC in 2017. GRAP is a set of stratified actions that are taken once the pollution level reaches a certain specified limit. It works only as an emergency measure
Government has opened the peripheral expressway around the capital to diverts non-Delhi destined traffic away.
3. Construction & demolition (C&D) waste management rules: Govt. has notified construction & demolition waste management rules.
As per the rules, all generators of C&D waste must segregate it into four categories– concrete, soil, steel and wood, plastics, bricks and mortar – and then either deposit it at collection centres setup by the local authority or hand it over to processing facilities.
Over the years, the System of Air Quality and Weather Forecasting and Research (SAFAR) has developed a system to calculate the contribution of stubble burning to Delhi’s pollution.
4. Tree policy: A new policy with an aim to preservation and transplantation of trees has been introduced by Delhi government.
5. CPCB monitoring: Central Pollution Control Board (CPCB) has deployed 50 teams for inspection in Delhi-NCR region. Inspection teams will visit the construction site and will levy fines in case of any violation of anti-pollution guidelines.
6. Red Light On, Gaadi Off campaign: A campaign ‘Red Light On, Gaadi Off’ has been launched by Delhi government to tackle air pollution. As per the government, switching off vehicle engines will not only stop pollution but also result in saving of ₹7,000 per vehicle every year.
7. Anti-Smog guns: Anti-smog gun is a device designed to reduce air pollution by spraying water into the atmosphere so that all the dust and polluted particles get clear from the environment. The gun is attached to a water tank built on a movable vehicle which can be taken to various parts of the city.
8. Smog Towers: They are large-scale air purifiers usually fitted with multiple layers of air filters which cleans the air of pollutants as it passes through them
- Use of Happy Seeders: By Happy seeders, farmers can sow wheat seeds with the stubble’s organic value-adding to the soil, without the need to clear it or burn it.
- ICMR tech: Indian Agricultural Research Institute (ICMR) has developed a solution that can be sprayed on crop residues and convert it into manure. This technique should be used on a wide scale all over the region.
- Commercialisation of paddy straw: Government should find ways to commercialize paddy straw, as wheat straw is useful farmers have found ways to use it, unlike paddy.
- More Smog towers: More smog tower and anti-smog guns should be installed to reduce the level of smog in the capital.
- Implementation of legislations: Environment-related Legislations must be implemented and followed in Letter and spirit. Many laws have been framed to protect the environment and their implementation on the ground is very lethargic.
Read more – Air pollution in India