From stubble-burning to smog

Smog has arrived once again – as it comes down this time of the year. Children have not gone to school. Air flights and normal road traffic will probably be disturbed.

We had discussed in this space earlier the role of petroleum, automotive vehicles and road traffic in causing air pollution and smog in Punjab and elsewhere. In the following, we will deal with the role and impact of stubble burning and will explore ways and means of handling and mitigating the issue as well.

The issue is full of controversies. On both sides of the border in our region, blame is being leveled that the stubble burning pollution is travelling from the other side. Both may be right as the area is contiguous and the wind direction keeps changing.

At least in India, farmers are downplaying the role of stubble burning in causing smog and are shifting the blame on other sectors. They are also contesting the role of machines in recycling stubble into the soil – terming it ineffective, expensive and unaffordable. High courts have been issuing edicts banning stubble burning but the ban has not been effective. A subsidy of IRS100 per quintal (100 kg) has also been ordered by the courts to help farmers meet the expenses of machinery in recycling the stubble.

There is no doubt that stubble burning is not the sole reason for smog. Traffic emissions, brick kilns, industrial pollution especially burning of dirty fuels and no pollution controls, dusty construction activities, all are contributors to the problem. However, in the autumn when rice is harvested on both sides of the border and the stubble has to be cleared within fifteen days in order to be able to sow a new crop – both the volume and the time enhance the intensity of the problem. So the cheapest and fastest way is to burn the stubble.

Expensive equipment and technology is around which can be used to clear the stubble without burning it. But only rich farmers can afford it. However, without a useful use of the stubble, nobody would have the incentive to invest in it. Indian Punjab alone produces 20 million tons of stubble, most of which is burnt in a month in October. A recent study in Pakistan estimates stubble burning at some two million tons appears to be an underestimation for a six million ton annual production of rice.

Overall, 60-80 million tons of agricultural waste and residue is generated in Pakistan annually. This can be a resource rather than a liability. It contains energy as is readily seen by the burning flames. Instead of wasting it, it can be usefully employed and can be used in producing electricity, and in the industrial and domestic sectors. Bio-fuels are a new product that is being increasingly produced from rice straw and other agricultural waste.

Raw stubble is, however, a liability and its burning is inconvenient and wasteful. For efficient and convenient use, it is converted into briquettes or pellets. The biomass is to be dried, crushed and pressed into pellets with or without the help of binding additives. Densification reduces volume, reducing transportation costs, and increases volumetric calorific value. It also slows down burning; raw biomass burns too fast making it uncontrollable and wasteful. Also storage becomes easier reducing volume requirements and increasing stackability. While biomass/stubble may be generated in a short time, it cannot be consumed instantaneously; it has to be stored for later sustained consumption.

Raw biomass is currently used by the rural poor in domestic cooking and even heating. In its raw form, it causes indoor pollution affecting women especially. In pellet form, it is less polluting and manageable. All rural areas are not equally endowed agriculturally. Pellets can make biomass transportable and tradable and converted into a saleable commodity. Currently, it has no value, except in some special cases such as Bagasse. If it has a value, it won’t be so mercilessly burnt as stubble is burnt currently.

Only 20 percent of the population in Pakistan has access to gas where a pipeline network is available. In other areas, charcoal, LPG and kerosene are used which are much more expensive. Gas is subsidized (cross subsidy) to small and medium consumers. Gas availability is going down and it is getting costlier, especially due to the advent of LNG.

Biomass pellets can be affordable. Biomass pellets have almost the same energy content as Lignite (Thar coal). Thar Lignite is being produced at a cost of $47 per ton. The government of Pakistan could encourage small, medium and largescale utilization of biomass including stubble – paddy waste. Small pellet producing plants can be installed on farmlands.

Model and demonstrating plants could be installed and easy credit terms provided.