As many as 34 percent of the people who spend most of their time indoors, in offices and at homes, have various types of respiratory diseases because of the indoor air pollution.
According to a survey conducted by Artemis hospital, 82 per cent of the offices in the national capital have unhealthy air quality.
The study said women and children were the most vulnerable.
Bad indoor air quality can cause Chronic Obstructive Pulmonary Disease (COPD) among women and aggravate Asthma symptoms among children.
"Unhealthy indoor air is also found to increase chances of developing Pneumonia in children, " the study said.
"Generally we give more importance to outdoor air pollution but we should be aware of both outdoor as well as indoor air pollution.
Considering the amount of time people spend breathing indoor air, it is important to keep a check of the indoor air quality, " said Himanshu Garg, Head of Department, Respiratory and Critical Care, Artemis Hospitals.
Garg headed the survey.
The survey was done under the initiative of Clean Air India Movement (CLAIM), one of the biggest initiatives on raising awareness around the health hazards of air pollution.
The Survey was conducted on 1, 500 people, from offices and houses across Delhi, Gurgaon and Noida having an average age of 39 years.
"Indoor air 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 of Respiratory Allergy & Applied Immunology department at Vallabhbhai Patel Chest Institute.