Experts say the ordinary masks are not of much use as they do not filter small particles that carry the virus.

'The demand for the masks, apparently due to the panic button pressed by the media, especially the TV channels, has increased manifold in the past four to five days. I alone have sold six months' stock in just three days and am waiting for more supplies from Delhi,' Motwani said.

'Several people who cannot afford costly masks or who do not have any idea about the variations in quality are using normal disposable masks for three to four days which is more harmful than not using the mask at all,' feels Ajay Goenka, a leading physician here.

'Though no case of swine flu has been detected in Indore, people are purchasing masks,' said Makrand Sharma of Kwality Drug House -- a leading wholesale chemist.

He added that 'around 2,000-4,000 masks were initially sold in the city every day. Now they are not available at most shops and some of the shopkeepers were even reported to be selling them at a higher price.'

The masks are available for a retail price of around Rs.100 each and the price might go up further as the demand rises and stocks dwindle, Sharma said.