New Delhi, Nov 7 (IANS): Thick dark smog across Delhi and national capital region (NCR) has started taking a toll on people's health and is hampering their ability to do their jobs efficiently, a survey said here on Monday.

The survey was done by the social development arm of the Associated Chambers of Commerce and Industry of India (Assocham). It interacted with human resource professionals in about 150 companies working in different industries both in public and private sectors in and around Delhi to evaluate impact of air pollution on companies' financial health.

The survey was conducted during the course of past one week.

"Air pollution in Delhi-NCR is not just devastating the environment but harmful amount of gases, dust, fumes and odour are causing breathing problems to people," said D.S. Rawat, Secretary General of Assocham releasing the chamber's survey.

"Companies should offer employees flexible working hours to cope with this problem," he said.

"Environment and air pollution related issues might hurt brand India and hit sectors like tourism, outdoor recreation as people tend to stay away from polluted areas so as not to breathe in dense and toxic air," Rawat added.

Most of the human resource (HR) professionals said they are facing staff shortfall ranging between 5-10 per cent with growing number of employees calling in sick.

"Persistent cough, burning eyes, itchy throat and respiratory or lung-related problems like asthma and bronchitis are the main reasons as to why many employees are not turning up for work, said many of HR representatives," the survey stated.

Though many HR professionals said they have installed air purifiers across their office and have advised their staff to use face mask, the severity of air pollution has certainly impaired performance through changes in respiratory, cardiovascular, and cognitive function.

Many private companies are allowing their employees to work from home while recuperating from their illness, the survey stated.