Composting is the primary, most widely recommended method for managing biodegradable (organic) domestic waste — such as kitchen peels, leftover food, and garden trimmings — once it has been collected and segregated from non-biodegradable waste.

The process relies on aerobic microbial decomposition: bacteria, fungi, and other decomposer organisms break down organic matter in the presence of oxygen, releasing carbon dioxide, water vapour, and heat, and leaving behind a dark, crumbly, nutrient-rich material known as humus or compost. When earthworms are used to accelerate this breakdown, the process is specifically called vermicomposting.

Municipal solid waste management rules require households and civic bodies to segregate waste at source into biodegradable, non-biodegradable, and hazardous categories precisely so that the biodegradable fraction can be diverted to composting instead of landfills.

Benefits of composting include:

• Diverting organic matter away from landfills, which reduces landfill volume, cost, and land requirement.
• Producing a natural, chemical-free fertiliser that improves soil structure, water-holding capacity, and nutrient content.
• Lowering greenhouse gas emissions, since decomposition in poorly managed, oxygen-starved landfills generates methane, whereas controlled aerobic composting minimises methane formation.
• Reducing dependence on chemical fertilisers, which in turn limits soil and water pollution.

The other listed methods are unsuitable or harmful: burning waste in the open releases smoke, particulate matter, and toxic gases and is banned under pollution-control regulations; sending organic waste for recycling does not apply, since recycling is meant for materials like plastic, paper, glass, and metal rather than biodegradable matter; and discharging it into sewers overloads sewage treatment systems and can contaminate water bodies. Composting therefore remains the standard and preferred practice.