- Road dust is the biggest contributor to PM 2.5 and 10 in Delhi
- Lack of enough vacuum machines to collect road dust causes its abundance
- Mixing road dust with synthetic polymers can help manufacture sand
New Delhi: Delhi is currently witnessing severe air pollution with massive spikes in levels of particulate matter (PM) 2.5 and 10. While factors such as stubble burning and vehicular emissions have been blamed, the biggest contributor towards Delhi’s air pollution – road dust – should also not be forgotten.
Dust in Delhi is not a new phenomenon. Most of Delhi’s roads have high silt concentration. Dust from constructions near roads also settles in roadways. Further, ill-maintained roads with potholes and broken parts are known dens of dust accumulation. Vehicular movement makes it worse and if one thing is constant and continuous in the capital, it is relentless vehicular movement. The 2016 study by Indian Institute of Technology, Kanpur that is presently doing the rounds to decode Delhi’s pollution, stated that road dust is the biggest contributor towards PM 2.5 and 10 emissions in the city. 56 per cent of PM 10 emissions were a result of road dust, while the percentage for PM 2.5 was at 38 per cent. Why has then the problem not been taken seriously enough?
The road length to number of vehicles ratio in Delhi is low, hence every road sees major traffic every day and road dust is inevitably formed. Manual sweeping has been around in Delhi under the supervision of the Municipal Corporation of Delhi, but that only spreads the dust more instead of containing it, and makes it worse, said Anumita Roychowdhury, Executive Director, Air Pollution, Centre for Science and Environment.
On December 16, 2015, the Supreme Court ordered the government of Delhi to tackle road dust on an emergency level and to procure vacuum cleaning machines which can gather road dust from at least the city’s busy roads. Till September 2017, a total of only 17 such machines were procured by various Delhi authorities. Of the 17, five are with New Delhi Municipal Council, six are with the Public Works Department (PWD) and six are with South Delhi Municipal Corporation (SDMC). The North and East wings of the MCD are yet to procure any such machines.
We have submitted a tender to procure at least five such machines which are expected to be with us by the end of November. Once they are here, we will use them extensively for dust removal from roads, said Dr Ranbir Singh, Commissioner, East Delhi Municipal Corporation.
Road vacuum cleaners are a definite solution for Delhi’s road dust problem, but the Environment Pollution (Prevention and Control)
Authority (EPCA) for NCR had also suggested some other measures to control Delhi’s road dust, of which sloping of roads was one. As per the recommendations, roads should be sloped in a way so that they are at their elevated highest at the centre and slope down on the edges. Sloped roads ensure that water goes into the underground drainage system instead of remaining stranded on roads and damaging them. But is the restructuring of Delhi’s road system a plausible solution?
Not all of it at once, of course but if the Delhi Development Authority can identify some of the roads which need urgent attention to address the dust problem, work can begin. Restructuring of a road means the road will have to remain shut for some time and a work of such scale involves clearances from a number of bodies, not just us, said Sanjeev Rastogi, Superintending Engineer, Public Works Department, Delhi.
The option of vacuuming dust off the streets is a good one, but alas, comes with a catch. The gathered dust needs to be disposed somewhere. Landfills, which already have their own problems are not an option and neither is disposing the dust in any water body, as that defeats the whole purpose of combating pollution. The EPCA recommendations had suggested using chemicals to bind dust particles and make them into a variant of sand. The critical shortage of sand in India is not unknown and a sand variant from road dust will actually be of help for the construction industry.
There is no dearth of road dust, not just in Delhi but across all major cities in India. In countries like Spain and Norway, road dust has been mixed with polymers to manufacture sand, and then using it for construction purposes. A similar model can be followed in Indian metros as well. If enough investment is made in developing technologies that can mix road dust with polymers and develop usable sand, we can have a successful model to follow, said Mrs Roychowdhury.
Now that the Delhi government has decided not to enforce the Odd-Even policy, the number of vehicles plying on the roads of the capital and generating dust will be same as usual. While it may be too late for this year, controlling of road dust and its cleaning must be prioritised throughout the next year to ensure that the major contributor to Delhi’s air pollution does not remain unchecked.