New Delhi: Indoor air contains two to five times more concentration of pollutants than outdoor air, and in some cases, the numbers are found to exceed 100 fold, said a recent survey. According to the survey, 47 percent people in NCR, mostly staying indoors during the day, have been found to have symptoms of the various respiratory disease. The diseases symptoms which were found among the residents included rhinitis, asthma, decreased resistance to respiratory infections and chronic obstructive pulmonary disease (COPD). The survey was done by the Artemis hospital in collaboration with the Air purifiers manufacturer Blueair. The brand has recently initiated the country's biggest awareness programme against air pollution, with several studies on the effects of outdoor and indoor air pollution among the citizens. A report of the World Health Organization (WHO) report showed that indoor air pollution accounts for nearly 3 percent of the global burden of disease. Around 4.3 million people, mainly women and children, die prematurely each year due to exposure to household air pollution. “Indoor air pollution is one such health hazard which silently entering our body and incapacitating us from inside. Its quality is equally or more dangerous than outdoor air pollution. Since we spend more time indoors, naturally the risk associated with indoor air is more.” said Raj Kumar, head Respiratory Allergy, and Applied Immunology at Vallabhbhai Patel Chest Institute, commenting on the survey.