What Causes Delhi’s particularly bad air pollution?
Air pollution in Delhi’s National Capital Region (NCR) is comprised of a complex mix of pollution from human activities  (vehicle emissions, industry, construction and residential fuel burning) as well as natural sources like dust and sea salt. The heavy concentration of particulate matter is greatly affected by meteorological conditions –in the winter, cool air causes “inversions” that stagnant the air and trap pollution close to the ground. Air flow patterns  from Afghanistan and Pakistan pick up emissions as they move over the densely urbanized regions of Punjab and Haryana where farmers burn the straw in their fields and pull this pollution into Delhi.  Pre-monsoon dust storms also contribute to air pollution in the region.

City activities also contribute to the air pollution. The NCR generates 10,000 tons per day of municipal solid waste, much of which is eventually burned, adding particulate pollution to the air (Guttikunda 2015) and  galloping urbanization brings massive construction projects to the area. In adddition, Delhi has more than 7.4 million vehicles on it’s roads, with an additional 1,200 added each day and the result is a pollution “hotspot.”

Graph 1.1: Particulate pollution decline and rise again due to rapid increase in vehicle numbers

EPCA graph 1
Source: Based on air quality data of Department of Environment, Delhi and motor vehicle registration data in Delhi Statistical Handbooks of different years. (“EPCA Report (February 2014) Report on Priority Measures to Reduce Air Pollution and Protect Public Health”)

It’s interesting to note that there is currently debate in the Indian government on the issue of cause and effect. A press release from India’s Ministry of Earth Sciences puts special attention to temperature and wind patterns in the winter contributing to the increase in hazardous pollution events.

On the other hand, the Environment Pollution (Prevention & Control) Authority  investigated the issue and reported to the Supreme Court the significant role of vehicles and vehicle emissions to rising air pollution in Delhi, stating that rapid motorization based on poor quality fuel and vehicle technology will make the air pollution trend irreversible. The report focuses on government standards and policies that have contributed to the current pollution problem and ends with recommended priority actions on the policy level.

Some salient points from this report:

  •  From 2002 to 2012, vehicle numbers have increased by as much as 97%, contributing enormously to the pollution load and direct exposure to toxic fumes.
  • The Price of Compressed Natural Gas (CNG): In 2002-03, CNG was cheaper than diesel by about 46.71%. But in December 2013, the price differential plummeted to 7.35%. Only after the most recent intervention to reduce CNG prices by Rs 15 per kg in February 2014 has helped to increase the differential again to about 35%. High CNG costs hurt public transport and undermine the clean fuel program.
  •   The gap between diesel fuel and petrol prices, which are skewed towards making diesel relatively cheaper, is leading to dieselization of cars. From just 4% of new car sales in 2000, diesel cars are now half of new car sales. The WHO has formally reclassified diesel emissions as class I carcinogen for its strong link with lung cancer –putting it in the same class as tobacco smoking.
  •   Emissions standards: only 38 cities and towns have the high-level Bharat IV standards in place for fuel and vehicles emissions.  The rest of India has the much more polluting Bharat Stage III standards in place. Equalivent to Euro IV standards, Bharat IV particulate standards are 50% cleaner than Bharat Stage III standards for cars and 81% cleaner for trucks and diesel buses. Though Delhi follows Bharat IV standards, significant cross-through traffic from other locals means that the city is greatly affected by high polluting vehicles. You can read more on emissions standards in India here.
  •   Non-polluting modes of public transportation are jeopardized. Currently it is too dangerous to walk and cycle safely in the city.  Road accident data for 2012 shows every hour a person is injured or killed in a road accident in Delhi.
  •   Buses are taxed more highly than cars adding to bus operation costs
  •   Car growth is explosive due to hidden subsidies for example the low cost of parking in Delhi when compared to parking in other international cities.

What part do emissions from India’s coal-fired power plants play in the pollution problem?

Nasa satellite data from December 2013 revealed that sulfur dioxide emissions in India increased more than 60% from 2005-2012. According to a press release from Nasa, this data corroborated other research concluding that as of 2010 India is the world’s second largest emitter of sulfur dioxide after China. That research also found that, at the time, half of India’s emissions came from the coal-fired power sector. Zifeng Lu, head of the research team responsible for the study added “long-lifetime, sulfur-containing air pollutants such as sulfate can be transported long distances to affect public health and the environment at a regional scale.”