Indoor air in Delhi is not fit to breathe and the elderly and children who spend a lot of time in offices and homes are the worst sufferers, a survey has found.

As per the survey, conducted by Artemis Hospitals as part of Clean Air India Movement (CLAIM), there is a correlation between indoor air quality and lung health of the people.

Due to unhealthy indoor air quality, about 34 per cent of people have one or the other airway disease and 47 per cent showed symptoms of respiratory diseases.

Eighty-two per cent of offices and houses surveyed have unhealthy air quality, according to the survey.

"Generally, we give more importance to outdoor air quality but we should be aware of both outdoor and indoor air pollution. Considering the amount of time people spend breathing indoor air, it is important to keep a check on indoor air quality.

"We hope the survey results will help initiate and channelise the discussions on the issue and draw meaningful conclusions," said Dr Himanshu Garg, Head of the Department of Respiratory and Critical Care, Artemis Hospitals.

The survey was conducted on 1,500 people across Delhi, Gurgaon and Noida, having mean age of 39 years.

"Since we spend more time indoors, the risk associated with indoor air is more. Women and children are most vulnerable...," said Dr Raj Kumar, Head of the Department of Respiratory Allergy and Applied Immunology, Vallabhbhai Patel Chest Institute.

Founder of Clean Air India Movement Vijay Kannan said "we all should plant more trees to reduce pollution.