One of India's thriving cities, Chandigarh has over 3,200 female sex workers, says a survey, but the police claim to have little or no idea about it.

A recent survey by the state AIDS Control Society has found 3,224 females engaged in prostitution in the city.

The figure has come as a "surprise" to the police officials, who claim they have been strictly monitoring prostitution in the 114 sq km city.

Though police officials claim they had arrested several prostitutes in the last few years, the survey shows that sex trade is thriving.

"If the police say they are ignorant of the sex trade, they are feigning it. We get many female customers seeking medicines for sex-related diseases that are possible only if they have multiple partners," says a leading chemist in the city's Sector 16 area.

"Sex workers usually avoid qualified doctors."

Unlike metros like New Delhi, Mumbai and Kolkata, Chandigarh - which has a population of over 910,000 - has no designated area for brothels to be run.

"Most of the trade is being run clandestinely by pimps through their network," a leading city hotelier, who claimed to know several such 'contacts', told IANS.

Also, the survey is unlikely to have covered all the prostitutes operating in the city and its two satellite towns of Panchkula and Mohali.

"Many girls operate from these two towns and other nearby areas of Chandigarh. Others come from smaller cities and towns in Punjab, Haryana and Himachal Pradesh. They would not have been covered in the survey," says a police inspector.

According to him, the number of female sex workers could be up to three times the survey figures.

Over half the sex workers are believed to be operating from the city's ever-expanding slums that have a population of over 300,000. Most people in these slums are migrants from Bihar and Uttar Pradesh.

The survey was done to map the drug users in the city and monitor their activities. The comprehensive mapping revealed that around 1,670 people were taking drugs regularly.