It is evident from various Hindu scriptures that the ancient Hindus had a clear insight into various aspects of the environment that are conducive for health and happiness of all life forms including the purity of water and air. Charaka (4 th century BC) and Sushruta (6 th century BC) show intimate knowledge of the purity of water and air and its importance for human life. Some of the important observations of these ancients seers of Hinduism are: Knowledge of Ancient Hindus Regarding Purity of Air Charaka held that the air, which is not in accordance with the season is not conducive to good health. Air that is excessively moist, harsh, speedy, cold, hot, rough or blocking, terribly noisy, whistling, smelling unsuitably or contaminated with particles from poisonous flowers (pollen), gravel, dust or smoke, etc., is unwholesome and is responsible for diseases and epidemics. Knowledge of Ancient Hindus Regarding Purity of Water Details of diseases that spread thr...