Heterogeneous photocatalytic oxidation (PCO) is one of the most active research areas in environmental purification. Recently, research on PCO technologies-based air cleaners and building materials has been intensively conducted for indoor/outdoor air treatment. The innovative technology is dedicated to decompose gaseous pollutants using photocatalysts under illumination of UV or solar light without extra energy added. Comprehensive knowledge on the properties and performance of PCO for treatment of air using batch reactors or continuous reactors has been established.

Presently in India, about 960 million tonnes of solid waste is being generated annually as by-products during industrial, mining, municipal, agricultural and other processes. Of this ∼350 million tonnes are organic wastes from agricultural sources; ∼290 million tonnes are inorganic waste of industrial and mining sectors and ∼4.5 million tonnes are hazardous in nature. Advances in solid waste management resulted in alternative construction materials as a substitute to traditional materials like bricks, blocks, tiles, aggregates, ceramics, cement, lime, soil, timber and paint.