The Harvest of Polluted Air
Current situation:
- Due to the yearly haze and pollution that passes over Delhi in October and November, construction projects have temporarily been put on stop, along with the movement of trucks and diesel four-wheelers that do not comply with BS-VI requirements.
- A case against agricultural stubble burning in the northern states, which is thought to be the main cause of the awful air quality in Delhi and the NCR, will be heard by the Supreme Court.
Is agricultural burning the primary cause of pollution in Delhi?
- Actually, the main reason for the smoke and haze over Delhi at this time of year is the burning of agricultural waste in Punjab and Haryana.
- At this time, burning-related particulate matter accounts for 30–40% of the PM2.5 concentrations in Delhi’s air. It is the major source of PM2 in the world. The majority of days during this period had 5 levels.
- Because a 30–40% increase in pollutants at any other time of the year would not have the same effect, the weather also has a significant impact. Burning agricultural waste in Punjab and Haryana during the months of May and June would not have had the same impact as it has right now.
- The weather, especially the heat, is the cause. Pollutants are carried higher into the atmosphere by rising hotter air. Before being disseminated, the polluted particles are lifted 2-3 kilometres above the surface, if not much higher.
- In comparison, the temperatures in October and November are not as hot. The current smoke and haze scenario is caused by pollutants that are restricted and have a tendency to collect at lower altitudes of the sky.
But why is agricultural waste burned?
- The after-harvest residue from the rice crop is what makes up this waste. There are burning customs outside of Punjab and Haryana as well. But compared to other states, the burning is significantly more widespread in these ones.
- This practise is quite recent, even in these states. The crop burning issue was not as serious even five years ago.
- Burning is necessary since there is only a very small window of time to prepare the fields for the upcoming crop. There is currently extremely little time in these states between the harvest of one crop and the planting of the following crop due to a modest alteration in the cropping pattern.
- If the first crop’s stumps were manually uprooted or cut, it can take more time to sow the succeeding crop. Farmers choose to burn these leftovers because it is a more convenient option.
So, is there no way to deal with this problem?
- Many solutions have been tested and are being tested right now. Among them are suggestions for altering the agricultural cycle, the use of automated harvesting tools to eliminate the need for burning, and the conversion of this waste into something more useful, such a source of energy, which may discourage burning.
- The government recently invested money to purchase the necessary tools or to test out various approaches to fixing this problem. But it’s obvious that these techniques and tools haven’t been used correctly.
Would the ban on diesel engines and construction vehicles be effective?
- 5 concentration is slightly impacted by construction. These processes frequently result in the release of larger particles, which raises PM10 concentrations.
- Therefore, it is not anticipated that limiting development will significantly alter the current situation.
- In reality, older lorries and diesel-powered automobiles and trucks make a major contribution to the high PM2.5 levels. Restricting their freedom of movement can also significantly improve the situation.
- The most polluting diesel vehicles, trucks, are not permitted to go through Delhi during the day.
- In reality, the PM2.5 levels differ significantly between day and night when trucks are only in action at night.
Why, despite rising pollution, is the government placing more of an emphasis on diesel vehicles than gasoline ones?
- CO2 emissions alone are not the problem. In addition to soot emissions, there are other dangerous contaminants for people. Diesel is less fortunate than gasoline in this way.
- Nitrogen oxides (NOx), which comprise the deadly nitrogen dioxide (NO2), the greenhouse gas nitrous oxide (N2O), and the nitric oxide (NO) that reacts with oxygen to produce the hazardous NO2, are created when air is heated in a car engine. Chronic respiratory issues are also more likely when nitric oxide is present alone.
- Three-way catalytic converters in petrol engines produce NOx emissions that are, on average, 30% lower than they would be in a diesel engine due to the reduction of these pollutants.
- Despite some estimates that the particle filters in modern diesel vehicles have reduced NOx emissions by 90%, diesel engines still emit fine particulate matter (PM) in their exhaust emissions. This is basically soot, which over time can result in cardiac and pulmonary issues due to even the smallest particles becoming deeply embedded in the lungs.
Why only BS VI diesel vehicles should be allowed:
- BS-VI stage is higher than BS-V stage. Petrol vehicle conversions from BS-IV to BS-VI just required catalyst and electronic control improvements, however diesel conversions required more expensive and technically challenging work.
- To lower particulate matter (PM) and NOx emissions, the BS-VI standards required manufacturers to install three pieces of equipment: a diesel particulate filter, a selective catalytic reduction system, and a lean NOx trap.
- Compared to BS-IV diesel vehicles, this resulted in a significant reduction in emissions but a rise in cost.
