Prof. Dr. P. K. Jena in Bhubaneswar, November 10, 2019: Our national capital Delhi, for the last several days, is covered with thick layers of smog all day and night. As a result, all the people living there being choked with poisonous gases including oxides of carbon, nitrogen and sulphur along with particulate matters (PM).

By inhaling these gases, many of them particularly the children and old ones are suffering from various types of deadly diseases like asthma, cold and cough, tuberculosis, cancer etc. Because of the heavy smog, the transport system including rail and air flights as well as trades and business activities are very much affected. The schools have been closed.

The polluting agents are mainly stubble burning in neighboring Punjab, Haryana and Uttar Pradesh, the burning of fossil fuels in transport system and industries, burning of garbages, construction of roads and houses in Delhi etc. Out of all these the contribution of burning of the stubbles towards pollution is nearly 40 to 50%. These besides generating the polluting gases generate a lot of particulate matters (PM) which are also highly hazardous.

At present, Delhi is the most polluted city not only in India, but also in the world. In Delhi, the PM level is much higher than that of any other city in the world. For example, in January 2015, the average PM2.5 level in Delhi was 226, whereas that in Beijing which was considered to be a polluted city was 95. That means Delhi air was more than two times as bad as that of Beijing air. At present it was reported that, Delhi’s Air Quality Index (AQI) is 999 where as those of the other cities in the world are less than 100.

In October 2017, the AQI of Delhi was also 999. According to the experts, the harmful effect in inhaling such polluted air is equivalent to smoking 45 to 50 cigarettes a day. The contribution of stubble burning in thousands of hectares’ of farmland in the three neighboring states, is mostly responsible for the polluted air of Delhi.

In order to avoid the environmental pollution which is also responsible for global warming and climate change, now more importance is given to use renewable energy from sun, wind and biomass all over the world. In the present scenario, the biomass is considered by scientists and technologists as the most potential material for producing renewable energy and can be effective to replace the polluting fossil fuels to a considerable extent. For examples, one ton of biomass can produce 85 KWHr electricity or 50 gallons (189 litres) of biofuel.

The two processes for conversion of biomass into energy namely through thermo-chemical, and bio-chemical processes are techno-economically viable. The thermo-chemical process includes combustion, gasification and pyrolysis. The bio-chemical conversion includes anaerobic digestion and fermentation. The stubbles which are now being burned in the field of Punjab, Haryana and Utter Pradesh are enormous in quantities. It is suggested that all these stubbles after the harvest of the crops, should be taken out from the field and used for producing bio-energy as it is being done for other agricultural and domestic organic wastes.

At present the biomass contributes about 14% of global energy supply. In India the technology for producing bio-energy from biomass is available and is being utilized. As a matter fact, in the year 2013 a total of 4449 MW equivalent energy has been installed under bio-energy in grid connected and off – grid capacity. In the country 4.5 million tons small scale biogas plant have been already established. Therefore, the stubbles should be collected and utilized for producing bio-energy.

The farmers in Haryana, Punjab and Uttar Pradesh should be advised to allow the biogas producing companies to collect the stubbles from them may be by playing some nominal amounts and set up the bio-energy producing units in nearby areas. In this way the bio-energy producing units will get the biomass for a small price and at the same time this will also solve most of the pollution problems not only in Delhi but also in these states. As the need for bio-energy is increasing rapidly in the country and also from environmental point of view, the stubbles which are plenty in quantity will add substantially to generate more bio-energy. Biomass availability in India has been estimated at about 5 million tons per year of which 120-150 million tons is available for power generation.

Government of India has a plan to increase the resource of biomass through plantation of trees. It is estimated that about 5 GW power can be harnessed from the biomass through plantation on about 2 million hectares of forest and non-forest degraded land. Now the use of stubbles will substantially add to this. Further, it is suggested that, in and around Delhi and also in the neighboring states, large scale plantation of fast growing species in barren areas and around cultivable lands should be taken up This will not only keep the atmosphere free of the polluting gases including particulate matters, but also provide some more biomass for producing bio-energy. With proper planning, coordination and cooperation of all concerned, it would be possible to keep the atmosphere clean in Delhi and neighboring states for healthy living.

Former Director General, Council of Scientific & Industrial Research, India