India generates 150-500 million tonnes of construction and demolition (C&D) waste annually. This volume is projected to grow significantly as the country strives to add 700-900 million square metres of commercial and residential space annually by 2030. However, despite the massive scale of waste generation, India recycles only about 1% of its C&D waste. This highlights a critical gap in the nation’s waste management and recycling infrastructure.

Waste Generation and Composition

Construction activities typically produce 40 to 60 kilograms of waste per square metre, while renovation and repair work generates around 40 to 50 kilograms per square metre. Demolition activities are the largest contributors, with pucca (permanent) and semi-pucca structures yielding 300 to 500 kilograms of waste per square metre. This waste, predominantly made up of concrete, cement, bricks, and similar materials accounts for up to 70% of the environmental impact associated with construction and demolition (C&D) activities.

Source: Chemicals of concern in construction and demolition waste fine residues: A systematic literature review

Circularity: An answer to the potholes

Circularity can be created at every stage of construction and demolition. The image illustrated below puts the spotlight on the construction phase and the end-of-life phase.

    Source: Circularity and sustainability in the construction value chain

This section explores some areas in which circularity can be implemented.

– Dust Mitigation

The construction industry is among India’s highest contributors to air pollution, emitting large quantities of dust, particulates, and pollutants. Improper disposal of C&D waste exacerbates environmental issues. There is dust generation throughout the process of construction, the image below highlights the dust pollution in the C&D waste management loop.

                                               Source: CSE

The major dust-borne materials generated during construction/demolition and renovation activities are soil, sand, gravel and cement. Handling construction materials and C&D waste can cause serious environmental and health issues due to dust emissions.

The Central Pollution Control Board (CPCB) has explicitly outlined strategies for dust abatement. Dust generated during loading, unloading, and other activities affects air quality on-site and off-site, leading to respiratory problems and irritation. To reduce dust, water sprinkling or fine sprays can be used at sites. Construction materials and waste should be covered during transport or storage, and dust-prone activities like crushing should be enclosed. Dumping waste on roadsides or non-designated areas must be avoided, and vehicles and equipment should be well-maintained to minimise emissions. Green buffers, such as shrubs and trees, can help trap dust. Workers should wear protective gear, and dry sweeping should be avoided to prevent dust from spreading. Using products made from processed C&D waste reduces illegal dumping and improves air quality. Managing construction materials efficiently and adopting eco-friendly practices can significantly reduce dust-related environmental impacts.

Compliance with the rules remains weak, and stricter enforcement is urgently needed. Currently, the rules focus on mitigating air pollution but are often implemented reactively during emergencies, such as the severe AQI crisis in Delhi last November. A proactive and consistent approach is essential to address air pollution effectively.

– Fly Ash- A tool for circularity

Fly ash, a by-product of coal combustion in thermoelectric power plants, offers immense potential for promoting circularity in the construction sector. In India, fly ash generation reached a staggering 1,677.30 million tonnes in FY 2022, encompassing ash stored in operational and non-operational dykes, ash ponds, and other repositories.

Fly ash is widely used in applications such as brick manufacturing, ceramics production, road construction, and, most notably, concrete production, including both conventional and geopolymer concrete. The image below highlights the distribution of fly ash usage across these sectors in India.

As a substitute for cement, fly ash reduces the reliance on virgin cement, offering both environmental and economic advantages. It enhances concrete workability and, at higher levels, decreases water and additive requirements. Fly ash also strengthens concrete and improves durability, providing superior resistance to chloride, sulfate, and acid attacks while enhancing corrosion protection.

Despite its proven benefits, 22% of fly ash remains underutilised in India. Leveraging its full potential could significantly reduce the demand for virgin materials, driving sustainability in construction practices.

– Recycling the C&D waste

The primary step after collection of C&D waste, in a C&D waste recycling plant, is to sort C&D waste. The C&D waste is sorted into three categories: (i) metals, wood and others, (ii) concrete waste and (iii) mixed C&D waste.

(i) Metals, wood and others (plastics, etc.) constitute 10% of the total C&D waste which is generally directed to specific facilities for reusing, recycling, or disposal.

(ii) Concrete waste constitutes concrete pieces larger than 65mm.

(iii) The mixed C&D waste constitutes of soil, sand, gravel, bricks and gravel.

The concrete waste and mixed waste are processed in wet and dry processing machines while the recycled materials derived from the concrete waste and Mixed C&D waste are recycled concrete aggregates (RCA), manufacturing sand, recycled aggregates (RA) and landfill soil.

By institution of recycling, the Indian economy will emit 40% less greenhouse gas (GHG) emissions and the use of virgin material consumption in construction will be reduced by 37% in 2050 and 24% in 2030 compared to the current procedure of operations. It also reduces the energy requirement; the table below compares the energy requirement between a virgin and a recycled material used for construction.

Source:Recycling of C&D Waste Material For Energy Savings In India

Challenges 

C&D waste management in India faces significant hurdles, including weak compliance, inadequate infrastructure, high costs, and limited stakeholder engagement. These challenges hinder circularity and contribute to the improper disposal of waste, requiring urgent action for sustainable practices. The table below highlights the various aspects.

                                                 Source: CPCB, CSE

Conclusion and Way Forward 

To address these challenges, India must adopt a multi-pronged approach. Investment in advanced waste processing facilities across urban centres is essential to improve infrastructure. Strengthening the enforcement of C&D waste management rules through penalties and incentives can ensure better compliance. Encouraging public-private partnerships (PPPs) can help scale up recycling initiatives by leveraging private sector expertise and resources. Awareness campaigns are needed to educate stakeholders about the economic and environmental benefits of recycling C&D waste. Additionally, promoting research and innovation in cost-effective recycling technologies and sustainable building materials can drive long-term solutions for effective waste management.

C&D waste represents a significant yet underutilised resource in India’s journey towards sustainability. By addressing gaps in infrastructure, policy enforcement, and stakeholder participation, India can transform its C&D waste management system into a model of circular economy and environmental responsibility. The time to act is now, to build a cleaner and greener future, brick by recycled brick.