Engineering & allied operations 120 Air pollution 110 Astronomy & allied sciences 102 General Book 60 Knowledge Western 60 History 45 Air 32 Biography 28 Applied physics 27 Chemistry & allied sciences 26 India 25 Pollution 25 Air Pollution 24 Leadership 22 Water pollution 21 AIR POLLUTION 18 Literature 18 Religion 18 Air quality management 17 Criticism and interpretation 17 Hinduism 16 Philosophy 16 Astronomy and Allied Sciences 15 Management 14 Medieval Indian history--Mysore history--Tipu sultan--Hyder Ali--Kerala history--Kerala muslims 14 Social Sciences 14 Engineering allied operations 13 History and criticism 13 Politics and government 13 Air sampling 12