Context: Recently, the National Green Tribunal (NGT) has directed the Centre to set up a fly ash management and utilization Mission for monitoring and use of the remains of burnt coal.

Key Points

• NGT directed center for scientific management and utilization of remains of burnt coal.
• It has also asked to take adequate action against non-compliant power plants.
• The Mission will be jointly headed by the secretaries of environment, coal and power ministries, keeping on board chief secretaries of respective states. 
• The panel of secretaries, in coordination with power plants and statutory regulators, will have to draw a roadmap for utilization and disposal of entire legacy fly ash as per remedial action recommended by an expert committee which was formed by the NGT.

Key Reason behind above move 

• Coal-based thermal power plants (TPPs), which generate electricity, also produce wastes or By-products such as Fly ash and Bottom Ash has failed to properly dispose of environmentally hazardous fly ash.
• Since 1999 Union Environment ministry had directed the use of fly ash and mandated a target date for all thermal power plants to comply by ensuring 100% utilization. But still, it is not fully implemented.
• Such failures have been found to have resulted in serious damage to the environment and the public health which need to be remedied in a mission mode as per mandate of Constitution of India and the NGT Act.

Fly Ash and Bottom Ash

• When Coal is burnt in the furnace, it produces ash particles. These ash particles cannot be disposed of openly because they have hazardous elements like sulphur, mercury, aluminium, chromium, selenium, lead, radioactive materials (Uranium, Thorium), etc.
• Ash particles which are heavy in nature and could not fly away, and hence stored at the bottom, called Bottom ash.
• Ash particles that are not heavy in nature and could fly away that is captured and stored, so-called as Fly ash.
• Due to its non-heaviness, fly ash is very fine in nature.
• Commonly it has been seen disposing openly and resulting in environmental pollution. Mainly air and water bodies get contaminated due to it.

Use of Fly Ash

• Cement-based products, such as poured concrete, concrete block,
• brick, Portland cement concrete, Asphalt concrete,
• in geopolymers, Mineral extraction, Waste treatment, and stabilization
• can be used as fertilizer Soil stabilization
• used as embankment and mine fill
• can be used in Highway development etc