Waste Crisis in Delhi and the Waste-to-Energy Conundrum

With over 20 million residents, Delhi is one of the largest cities in the world. This growth has led to a sudden increase in the generation of municipal solid waste. Delhi produces around 14,000 tons of municipal solid waste every day which is enough to fill a number of football fields daily, and it keeps piling up. The waste management infrastructure in Delhi is struggling to keep pace with the city’s growth.

The municipal waste in Delhi is a complex mixture of:

1. Combustible waste – accounts for 30–35% of the total but only 10% is genuinely non-recyclable and suitable for waste-to-energy conversion.
2. Plastic waste – 15% of all wastes, out of which single-use plastics is approximately 5%.
3. Recyclable materials – Only 2.4% of solid wastes.

This means that most of Delhi’s wastes, especially plastics, end up in landfills or dumpsites scattered around the city, rather than being recycled or safely disposed of.

The Menace of Plastic Waste

Every day, Delhi produces more than 1,060 tons of plastic waste, much of it is single-use plastics. These plastics are lightweight and easily carried by the wind, so they travel far beyond landfill sites. It’s not unusual to see plastic bags tangled in trees, clogging drains, or drifting through neighborhoods far from any official dumping ground. This widespread plastic pollution is a daily reminder of the city’s solid waste daily generation challenge.

The Problem of Legacy Waste

The most visible manifestation of Delhi’s landfill overflow can be seen at Ghazipur, Bhalswa, and Okhla – large mountains of waste made from what is called legacy waste: millions of tonnes of garbage that have accumulated over many decades. These landfills are not just eyesores but also environmental hazards. Methane gas leaks from the decomposition of waste, furthering air pollution and climate change. Toxic leachate seeps into the ground, contaminating water sources and threatening public health.

Are Waste-to-Energy Plants the Answer?

Waste-to-energy plants, including the ones at Timarpur and Okhla, have been promoted by the government as the solutions to Delhi’s waste crisis. However, these plants are facing major hurdles:

• Only a small fraction of Delhi’s waste is suitable for incineration; most of it is either recyclable or too wet and mixed to burn efficiently.
• The volume of waste far exceeds the capacity of the few existing plants; most of the rubbish piles up in the landfills.
• Incineration has the risk of releasing harmful pollutants if not judiciously managed, hence affecting air quality.

So, although the relief provided by waste-to-energy plants is considerable, they are not a panacea for Delhi’s waste management problems. The simple explanation is that the city’s daily waste generation outpaces the solutions at hand. The overflowing landfills serve as a reminder of how strained the system is; low rates of recycling mean that plastic and other waste streams just keeps piling up.

Segregate or Incinerate: The Missed Opportunity?

Waste segregation issues lie at the heart of Delhi’s growing waste crisis, making waste-to-energy plants ineffective and posing a serious risk to public health. Of all the waste generated in Delhi, only about 30–35% is capable of being burnt to produce energy. Within that fraction, only about 10% is truly non-recyclable and suitable for incineration. The rest could be recycled or reused if it were separated properly at source.

Nevertheless, mixed waste dominates the feeding material sent to waste-to-energy plants. Valuable recyclables and compostable materials get burned alongside the non-recyclables, a practice not only wasteful but also illegal under the solid waste management by-laws of India.

Delhi’s segregation-related issues have their roots in some very serious underlying problems:

• Lack of public awareness: Most households and businesses are not aware of how and why to segregate their wastes.
• Poor enforcement: There is very little oversight and no penalty for failing to segregate the waste, so most people don’t bother.
• Inadequate infrastructure: Even when you want to separate the trash, the city’s collection system often mixes it all together again.

The incineration of mixed (or unsorted wastes) in waste-to-energy plants aggravates the problems:

• Emissions spike: The incineration of mixed wastes emits emits more toxic pollutants, including dioxins and furans, compared to the combustion of properly segregated, high-caloric waste.
• Ash overload: The MSW incineration process produces a huge amount of bottom ash and fly ash; the former remains in the furnace while the latter go up into the air. Fly ash is particularly harmful because it may drift into nearby homes and even land on food.
• Inefficiency: Waste-to-energy plants are designed to burn dry, high-caloric value combustible waste. When wet and recyclable materials are added in, the plants struggle to efficiently generate electricity, undermining the entire point of the technology.

Though ambitious, the Delhi 2025 goals related to waste segregation are a far cry from reality. The inflow of mixed waste to the various waste-to-energy plants in the city cripples their effectiveness. So, rather than converting trash to clean energy, these plants become sources of pollution and mountains of toxic ash—problems that spill over into the daily lives of residents. Until segregation at source becomes a reality, Delhi’s waste management system will continue to be a non-fulfilled promise with severe implications for the environment and public health.

Waste-to-Energy Plant and The Ash Problem

The ash generated by waste-to-energy plants is a chronic, toxic problem Delhi is still trying to handle. WTE plants burn municipal solid waste at high temperatures, generating heat that boils water into steam, which, in turn, powers turbines to produce electricity. But this process also results in the production of two kinds of ash – bottom ash and fly ash. Although both are hazardous, it is the fine, powdery fly ash that often escapes the WTE plant’s boundary, drifting through the air, and at times even into households.

The heavier residue that settles at the bottom of the furnace is called bottom ash. Fly ash is lighter and usually more hazardous. It can easily go airborne, therefore traveling far from the plant, and is many times seen coating window sills and balconies and, sometimes, the lungs of residents living nearby. In places like Sukhdev Vihar, fly ash has become an everyday nuisance and a public health threat.

The ash from waste-to-energy plant has an environmental impact that is not constrained to air pollution alone. The poor management of ash in WTE plants has resulted in serious water contamination. When the ash is thrown without caution, mostly in areas far from landfills due to laxity in regulatory compliance, toxic chemicals can leach into the soil and groundwater. The leachate contaminates the local sources of water and, in turn, affects the health of the people. While policies have been put in place requiring that a WTE plant be sited near engineered landfills, such rules are usually circumvented or poorly implemented. Without a robust, citywide ash management and a sustainable waste-to-energy strategy, hazardous dust keeps circulating and settles on homes and in the lungs of residents.

Emissions from waste-to-energy plants have grave consequences for public health. Fine ashes can ignite respiratory problems, exacerbate asthma, and increase the risk of long-term health problems. The environmental impact of waste is no longer confined to overflowing landfills but has now become a daily concern for those living near waste-to-energy facilities.

Bottom Line

Delhi’s experiment with waste-to-energy has created a new kind of waste conundrum. Ash, once thought to be the end of the story, is now at the center of a growing environmental and public health crisis. The transformation of Delhi’s trash into useful energy is more complicated than it sounds. Without proper segregation and responsible ash management, the waste-to-energy plants risk merely trading one set of problems for another. Community action, smarter policy enforcement, and finally taking a hard look at what we throw away and where it ends up-that is how to make real progress.