Stubble burning is one among many causes of bad air

Air pollution in Delhi and the National Capital Region (NCR) attracts enormous attention, but it is usually restricted to the months of October and November, when the farmers of Punjab and Haryana burn the stubble after using combined harvesters for their paddy crop.

Pollution levels in several other cities of north India remain much higher than the WHO recommended levels for several months in the year — but that is not considered newsworthy. Even in the NCR, the air pollution levels in other months do not invite much attention. However, it is time the governments showed seriousness in tackling the issue.

The highest level of pollution in Delhi this year (pm 2.5), was recorded on November 12 (due to crackers burst on Diwali), between 11 pm and midnight, when it reached 957 μg/m3. This was only slightly better than Ahmedabad’s pollution levels which peaked at 999 μg/m3.

Now that both Punjab and Delhi are ruled by the Aam Aadmi Party, it is very convenient to blame it for elevated levels of air pollution. But, science provides a balanced and impartial view of sources and drivers of air pollution in Delhi.

The Indian Institute of Technology Kanpur has been studying this for several years and in 2016 it submitted a report titled ‘Comprehensive Study on Air Pollution and Green House Gases (GHGs) in Delhi’. Again, in September 2023, IIT Delhi, IIT Kanpur, and TERI submitted a detailed report to the Delhi Pollution Control Committee. This is based on their study of sources of pollution in the winter of 2022-2023.

These highly regarded technical institutions set up a monitoring station at Sarvodaya Bal Vidyalaya, Rouse Avenue, New Delhi, which measured not only pm 2.5 particles in the air but also nitrogen dioxide (NO₂), other nitrogen oxides (NO_x)_, carbon mono-oxide, sulphur dioxide, ozone, elemental carbon, organic carbon, Polycyclic Aromatic Hydrocarbons (PAHs), elements, ions, secondary inorganic and organic aerosols, molecular markers, and other organic compounds.

The study found that Secondary Inorganic Aerosols (SIA, primarily sulfate, nitrate, and ammonium), which can travel long distances, made the highest contribution (of 32 per cent) towards air pollution. Particles of sulphate, nitrate, and ammonium are formed in the air from the interaction of various gases. Such gases are produced from brick kilns, which are in abundance around major cities, powerplants, refineries of petroleum crude, vehicles, open drains, and industrial units releasing gases. Organic waste decomposition and open drains also contribute to these SIAs.

The study found that the SIA was followed by biomass burning which contributed 24 per cent towards air pollution. The contribution of vehicles was estimated at 17 per cent.

The impact of crop residue burning was estimated to be 22 per cent during November 1-25, 2022. On certain days it exceeded 35 per cent.

The report recommends that all sources within and outside Delhi need to be controlled if air quality is to be improved.

One of the recommendations is to encourage all the restaurants and eating joints, having a seating capacity of more than 10 persons, to move from coal to gas-based or electric appliances. Ash and residue from the tandoor, etc. should not be allowed to be disposed of near the roads. It is not very difficult for the Government of Delhi and adjoining states in the NCR to implement this recommendation.

The burning of plastic, rubber, polyethene, and paper waste is quite common across India. These fumes are carcinogenic. Burning of leaves and wood to stay warm during winter, especially by poor people, is also quite common across north India. Providing gas or electric heaters at the peak of winter may prevent this.

Similarly, burning of solid waste by municipal authorities should not be allowed under any circumstances. This is  entirely in the hands of government-run municipal bodies.

The report also recommends that households should be turning towards clean fuel. As per the NFHS-5, 98.9 per cent of households in Delhi were already using LPG for cooking. However, in the rural areas in other districts of the NCR, the use of unclean full must be carefully studied and prevented.

While the steps required to check stubble burning are much debated, they are more difficult to implement as long as electricity for agriculture remains free and paddy cultivation in Punjab continues to be the most remunerative among all the crops.

Punjab and Haryana, the original green revolution states, need a financial package from the Centre to achieve a reduction of the area under paddy/rice. However, this is not even under discussion between these states and the Union government.

Both the Bharatiya Janata Party (BJP) and the Congress have promised a bonus on paddy in Chhattisgarh, Madhya Pradesh, and Telangana in the ongoing assembly elections. This is ironic as these states also do not have a surplus of underground water. It would be unrealistic to expect that farmers in Punjab are not keenly watching these poll promises.

While the pollution caused by stubble burning in Punjab invites more media attention, the Union government, along with the Government of NCR states should show by their actions on other sources of air pollution that they are serious about tackling the challenge.

Siraj Hussain is former Union Agriculture Secretary.

Disclaimer: The views expressed above are the author's own. They do not necessarily reflect the views of DH.