CONTRIBUTORS TO AIR POLLUTION  

1. Context 

2. Agricultural burning

• At this time of the year, the burning of agricultural waste in Punjab and Haryana is indeed the dominant reason for the smoke and haze over Delhi.
• The particulate matter from the burning contributes 30-40 per cent of the PM2.5 concentrations in Delhi's air during this time.
• It is the single largest source of PM2.5 levels on most days during this period.

2.1 Role of Weather 

• However, the weather plays a critical role as well a 30-40 per cent rise in pollutants at any other time of the year would not cause the same impact.
• Agricultural waste burning in Punjab and Haryana happens in May and June as well, although on a smaller scale.
• At that time, it accounts for about 15-20 per cent of PM 2.5 Concentrations in Delhi's air.
• But the air quality over the capital hardly ever becomes this bad.
• The reason is the weather or rather, heat. Hotter air rises higher above the surface and takes the pollutants along with it.
• The polluting particles are lifted 2-3 km above the surface or even higher, before getting dispersed.

2.2 Reasons for agricultural waste burning

• This waste is the remains of the paddy crop after it has been harvested.
• This kind of burning is not specific only to Punjab or Haryana.
• However, the scale of burning in these states is much bigger than elsewhere.
• Even in these states, this practice is relatively new.
• Even 10 years ago, the crop-burning problem was not this acute.

• The traditional method of manually uprooting or cutting, the stumps of the previous crop are time-consuming and can delay the sowing of the next crop.
• So farmers resort to the easier option of burning these remains.

2.3 Solutions 

• Hundreds of crores have been allocated in the last few years to buy the necessary equipment or to try out alternative methods of dealing with this problem.
• But clearly, these equipment and methods have not been deployed effectively.

4. Construction Sector Contribution 

• Construction has a small contribution to PM 2.5 concentration.
• The particles released from these activities are usually larger and add to PM10 concentrations.
• The banning of construction is unlikely to have any significant impact on the prevailing situation.

5. Diesel vehicle's Contribution 

• Diesel vehicles, particularly older trucks, are indeed important contributors to high PM 2.5 levels.
• A ban on their movement can help in improving the situation somewhat.
• However, trucks, which are the biggest generators of pollutants in the diesel vehicle segment, are not allowed to move inside Delhi during the day in any case.
• The movement of trucks only at night results in a significant variation in the PM 2.5 levels between day and night times.

For Prelims and Mains