Air pollution in and around the capital Delhi has reached alarming levels. On the other hand, the air pollution has crossed 2000 AQI (Air Quality Index) in two cities of Pakistan, Lahore and Multan. Keeping this in mind, the government of Pakistan has imposed a complete lockdown in both these cities.
Air pollution in the Indus-Gangetic plains crosses dangerous levels every year in winter. In North and Central India, stubble burning begins after Diwali. Due to which pollution increases. Currently, in the satellite images released by NASA, large parts of India and Pakistan are seen covered by a blanket of fog.
Dust from Pakistan and Afghanistan is increasing Delhi's pollution In winter, 72% of Delhi's winds come from the northwest. With these winds, dust from Rajasthan, Pakistan and Afghanistan reaches the Delhi-NCR region. Also, due to thermal inversion, pollution cannot spread to the upper atmosphere. It grows rapidly in areas around Delhi.
For the last 20 years, a 3 km thick layer of fog is continuously observed during the winter season from Peshawar to Dhaka. This layer becomes denser in winter season. Delhi is landlocked, meaning it is surrounded only by land and no sea. In such a situation, the air pollution here crosses the critical level.
Thermal inversion is the main cause of air pollution in Delhi
- Temperature generally decreases with increasing altitude.
- When temperature also increases with increase in altitude, it is called thermal inversion.
- This happens because a layer of warm air sits on top of a layer of cold air.
- During the winter months in Delhi, fog gets trapped below the warm air layer, close to the ground.
- Due to the rising cold it cannot spread upwards and the pollution particles get trapped in it.
Government of India initiative to curb air pollution
- To stop farmers from burning stubble, the government has launched the Crop Residue Management (CRM) scheme. Under this scheme farmers are given subsidy to buy Super SMS attachment, Turbo Happy Seeder, Rotavator and Super Seeder. These machines are helpful in removing stubble without burning it.
- After the Supreme Court's strike on November 18, the Delhi government has implemented the fourth phase of the Graded Response Action Plan (GRAP). Under this, measures like closure of thermal power plants and ban on construction activities are taken.
- Apart from this, the Delhi government also takes steps to control pollution through 'war on pollution', change from BS-IV to BS-VI, electric vehicles (EV), odd-even policy.
America-Britain controlled air pollution by promoting public transport
- The US government established the Environmental Protection Agency (EPA) in 1970 by passing the Clean Air Act. This agency was given legislative powers to control pollution. The EPA successfully controlled vehicle pollution by adopting stricter standards.
- The EPA began phasing out lead in gasoline in the 1970s and banned leaded gasoline altogether after 1995. As a result, air lead levels fell by 94% between 1980 and 1999.
- Many cities in Britain, Australia, America and Sweden have made public transport completely free to control air pollution. Luxembourg was the first in the world to introduce free public transport.
- Mexico started the odd-even scheme in 1979 in the capital, Mexico City, to control pollution. Later many other countries of the world adopted this model. The Delhi government adopted this model in 2016.
- Air pollution was a major problem in China until a few years ago. China implemented a series of air pollution control programs to overcome it. Under this, Beijing promoted urban rail expansion, used high-resolution satellite remote sensing, laser radar and modern techniques, and built a modern integrated air quality monitoring network.
Image Credit: (Divya-Bhaskar): Images/graphics belong to (Divya-Bhaskar).
