In Tamil Nadu's Thoothukudi district, famous for its salt farms, Tuticorin Alkali Chemicals and Fertilizers produces soda ash by recovering more than 90 per cent of the carbon di-oxide it generates from its coal-fired boilers - used for heating. A first in the world, according to them. Soda ash, is used as a raw material for glass, detergents and baking soda among others.