The powerful oxidative action of ozone provides basis for development of novel or improved technologies which are widely used in ecology and industry. Special attention is paid to purification of waste gases, water, and soils. The disinfection and cleaning of drinking and process water are considered in detail. Applications of ozone in chemical, pharmaceutical and perfume industries, cosmetics, cellulose, paper and sugar industries, flotation, microelectronics, and many others are also examined in the review