Did Delhi’s poor waste management add to severity of floods?

Several parts of the national capital, Delhi, were severely inundated in July 2023 following heavy rains. The city’s disconcerting and impaired model for waste management may have added to the severity of the flood.

The city generates 11,328 metric tonnes of garbage every day and all the solid waste generated gets collected, claimed a state-level committee headed by the chief secretary, Delhi, in April 2023. Nearly 62.5 per cent of this waste, amounting to 7,086 tonnes, is processed daily in its waste-to-energy plants, the committee added.

However, a 2022 Down to Earth report revealed that the three dumpsites in Delhi continue to receive 6,250 tonnes of fresh mixed waste every day — most of which is unsegregated.

Also read: Yamuna claims back Delhi: Several parts of capital witnessed floods after a generation

Moreover, the Central Pollution Control Board’s annual report for solid waste management 2020-2021 revealed that Delhi has the highest per capita waste generation rate of 450 grams per day. The report also disclosed that as much as 263 tonnes of solid waste generated every day in Delhi is unaccounted for. This indicates while the waste was collected, it never reached the processing centre or the dumpsite for unscientific disposal.

A part of it could be attributed to the waste management workforce that pulls out a lot of valuable and recyclable plastic before depositing it in the secondary collection points or the transfer stations in the city. A considerable portion of this unaccounted waste leaks into primary and secondary drains that would eventually enter the Yamuna.

Waste collection

Delhi’s model for waste management is one of a kind. The municipal administration does not undertake the door-to-door collection in most parts of the city and is being collected by informal sector players.

Areas to be serviced are held by informal players — waste pickers cannot provide this service randomly – instead, a catchment area of about 350-500 households is bought and sold among informal players.

Catchment areas are sold anywhere between Rs 80,000 and 250,000. The informal player who secures the catchment area by paying a one-time cost mobilises one informal worker to service a cluster of households. The informal player collects a user fee of Rs 100-Rs 250 every month from these households.

Solid waste collection is not regular and consistent in many areas serviced through this model. The informal worker collects unsegregated waste and retrieves most of the valuable and recyclable materials like plastics, metal, glass and paper.

The remaining waste is dropped off at the nearest secondary collection point to be dealt with by the municipal authorities. The city administration transfers this waste either to the four major waste-to-energy plants or the three dumpsites in the city.

Despite collecting a sizeable amount of solid waste from the city every day, more than 6,000 tonnes of unsegregated waste reaches one of the three dumpsites — Bhalsawa, Ghazipur or Okhla. Moreover, two of these three dumpsites are close to drainage systems that eventually meet the Yamuna.

Google Earth snapshots of Wazirabad nullah and Bhalsawa dumpsite (right) and Shahadra drain and Ghazipur dumpsite (left).

Waste processing

Source segregation is a non-negotiable aspect of the scientific management of solid waste. When solid waste is segregated at the source, the value of any stream of waste rises exponentially — non-recyclable waste, being an exception, is a burden on the city administration in any scenario of waste management.

The level of source segregation varies between 10 and 90 per cent in various wards of Delhi, according to the latest update provided by the Delhi Pollution Control Committee.

However, enough information about waste segregation in wards has not been provided. Moreover, source segregation has not been observed in a majority of the wards in Delhi.

Again the informal sector workers are the enablers of source segregation, but segregation by informal workers is strictly limited to what they can sell in the open recycling market. Also, informal workers are not trained to collect segregated waste and, most of the time, end up mixing waste. This means that mixed waste is received in transfer stations, also known as Dhalaoghars, in most parts of the city.

Delhi’s waste processing capacity is limited to treating 71 per cent of the solid waste generated in the city. Roughly 90 per cent of this capacity, i.e. 7,250 tonnes per day (TPD), is met through burning the waste in Delhi’s four waste-to-energy plants in Ghazipur, Bawana, Tehkhand and Okhla.

The city has plans to increase its waste processing capacity by 6,402 TPD. However, 94 per cent (6,000 TPD) of this expansion capacity is attributed to the development and expansion of waste-to-energy plants.

The city administration claims that a part of this capacity will also include biogas and compressed biogas (bio-CNG) technologies. However, the processing capacities of these promising and proven technologies have been restricted to 400 TPD.

Also read: North India Deluge 2023: Yamuna breaches evacuation mark in Delhi; expert calls flood policy ‘absolute failure’ 

This highlights the national capital’s reliance on flawed technologies such as waste-to-energy to dispose of its garbage. Proposals to expand these waste-to-energy plants and develop new ones have been put forth and approved, proving there is no course correction in sight.

Delhi’s already crumbling waste management system struggled to match the waste processing pace with the waste generation rate during the floods in July 2023.

A waste-to-energy plant could not receive waste from the city government for over a week after heavy rains, an operator said on condition of anonymity. This was because the waste had turned into a slurry due to uncovered vehicles used for transportation during heavy rains.

The reason was that waste was received in the form of a slurry because of the heavy rains due to uncovered vehicles used for transportation. “Due to this, the moisture content of the waste being received was over 70 per cent and had a calorific value of less than 800 kilo calories per kilogram,” he added. All the waste which was supposed to be received by the plant every day is now being diverted to one of the dumpsites.

In some cases, such as that of the Bawana waste-to-energy plant, the city administration offers a tipping fee of Rs 1,700 per tonne of waste for the collection and transportation of waste to the facility. 

Waste-to-energy plants have a very high reject ratio; for every tonne of waste that is burnt, 300 kg of waste has to be disposed of in landfills. This means a plant that is designed to handle 2,000 tonnes of solid waste per day will generate 60,000 kgs of reject, which have to be landfilled.

Delhi can change the status quo by enforcing source segregation, which is required by the bye-laws, holding bulk waste generators accountable for handling their organic component of trash and investing in decentralised waste management methods.

Once Delhi generates more than 5,000 tonnes of wet waste and achieves source segregation, several bio-CNG (economically and environmentally proven mode of waste to energy) plants can be commissioned within the city. Bio-CNG offers better rates and higher offtake than electricity derived from mixed municipal solid waste to energy plants and can help our public transport systems run on cleaner fuels.

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