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The mountains of wet waste produced by Chennai everyday due to lack of waste segregation are emitting large amounts of the most potent greenhouse gas of all — Methane. An initiative called Climate Trace that identifies major sources of greenhouse gas (GHG) emissions across the world, using satellites, Artificial Intelligence and conventional data sources shows major sources of GHG emissions in the Greater Chennai area.
Methane is released by the decomposition of organic matter, which continues to be dumped in large quantities in Chennai’s suburban municipal waste landfills, in spite of a professed programme to segregate solid waste at source and compost the biodegradable part under controlled conditions.
The high-tech system, Climate Trace, estimates emission volumes for climate change mitigation action. The multi-source emissions monitoring mission has been launched by the former US Vice-president and climate activist Al Gore, as an information tool to advance the goals of the Paris Agreement on Climate Change.
Zooming in on India on the Climate Trace map and scrolling down to the city level shows several major sources of GHG emissions in the Greater Chennai area, the most prominent of which is Chennai Airport, followed by waste dumping sites in Perungudi, Kodungaiyur, Madhavaram, Perungalathur — Tambaram, Sunnambu Kulathur and Athipet — Ambattur, among others. The target gas that is assessed in all these locations under the “waste” parameter is methane, a familiar and potent GHG, much more damaging than carbon dioxide. Several other significant sectors are measured too, such as energy production, industry, transport, and so on.
A clean up act
Localising the Climate Trace data should be a welcome feature, since it would give the Tamil Nadu government, the Greater Chennai Corporation (GCC) and other agencies fine-grained knowledge, and this would make it easier to approach international bodies, the UN system and even domestic funders for assistance to do a clean-up.
What the GCC and suburban municipal bodies such as Avadi and Tambaram Corporations, a dozen big municipalities and town panchayats are supposed to do is move towards source segregation of methane-generating biodegradable waste, mostly from houses, and compost it under controlled conditions, so the methane is not released into the atmosphere. Biogas plants are another way of using biodegradable waste, generating valuable fuel.
The annual report from Tamil Nadu to the Central Pollution Control Board for 2020-21 says the State produces a staggering 13,422 tonnes of solid waste per day, although it does not provide a separate figure for Chennai. Official claims put the volume of solid waste generated in the Chennai area to be anywhere between 5,200 and 5,600 tonnes per day. Since the ‘wet’ fraction of the waste could be 40% to 60%, the potential to produce a large volume of compost and biogas is self-evident not just in Chennai, but other cities and towns. Yet, there is no move to make such solutions available without much cost to the residents.
Official claims put the volume of solid waste generated in the Chennai area to be anywhere between 5,200 and 5,600 tonnes per day
Officially, of course, Chennai has been working to reclaim its traditional waste dumping grounds in Pallikaranai and Kodungaiyur, and made recent announcements to that effect. A plan to spend Rs 648 crore on a 252-acre site there to remove the small mountain of legacy waste has just been green-lighted by the Chennai Corporation Council.
A problem of measurement
On the one hand, Chennai and other urban agglomerations struggle to manage their ‘wet’ waste, while nationally, it is imperative for India to measure and report its GHG emissions to the UN Framework Convention on Climate Change as mandated by the Paris Agreement. India and other developing countries have a less rigorous mandate to report their emissions compared to the developed nations, but all members of the Paris Agreement are bound by enhanced transparency norms, which will particularly come into play in 2024 under the pact.
The emergence of remotely sensed carbon emissions estimates using satellites, land and sea-based sensors, public data, all aided by artificial intelligence and computations, highlight the need for Tamil Nadu to get its act together on solid waste management, dump sites, source segregation, composting and tapping of methane through biogas units. As noted earlier, more accurate measurement data help formulate remedial programmes and make a credible case for funding.
Recent media reports indicate that Chennai’s waste handling system, run partly by private entity Urbaser Sumeet, has not been meeting legal requirements. Even where segregated waste is handed over to agency staff, it gets remixed with wet waste in big bins, after the employees have extracted what is of cash value to be sold at local informal recyclers.
Public suggestions that the compost from municipal waste produced be sold through Urbaser personnel and also at each GCC ward office has not elicited a response.
Even where segregated waste is handed over to agency staff, it gets remixed with wet waste in big bins, after the employees have extracted what is of cash value to be sold at local informal recyclers
The official Indian estimate of methane emissions submitted to the UNFCCC (United Nations Framework Convention on Climate Change) in 2021 (the stipulated biennial update) is 14% of national GHGs at 409 million tonnes CO2 equivalent. Global estimates also say India’s emissions from agriculture are the highest in the world, at over 13% of the world’s total, partly due to the presence of a large number of cattle.
These startling figures should prompt municipal authorities to cut methane emissions from municipal waste sources in large cities such as Chennai.
Other sources to cut are transport emissions, which will require a speeding up of the electrification programme for buses. Whatever choices the government makes now — on technologies for waste management, biogas promotion — the effects will be felt for years. Purchasing poor quality buses run on diesel and maintaining them badly would have a lock-in effect for at least nine years, going by the replacement schedules for these vehicles.
A greener approach would dramatically scale up urban, decentralised composting of wet waste, with concomitant effects on greening of Chennai and suburbs. It would also mean not allowing the real estate lobby to get wetlands denotified and changed into residential areas, some prominent instances of which have been noticed in recent weeks in the city.
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