Delhi has become an "important transit point" of narcotics and the Union Home Ministry attributes it to the capital's proximity to opium producing states like Uttar Pradesh, and being the centre of the transportation network.
Statistics available with the ministry reveal while 1,140 cases were registered by the Delhi Police in 2005, as many as 790 cases have been registered till mid-July this year.
Sources in the ministry said 1,808 people were arrested last year while the figure for this year was 1,013 so far.
The main recoveries included ganja - 2,907 kg in 2005 and 1,204 kg so far this year, charas - 227 kg last year and 125 kg this year and smack and heroin - 117 kg in 2005 and 69 kg till mid-July, they said.
Sources said 108 kg of opium was seized in 2005 but the figure was quite low so far this year at 8.5 kg. Poppy seeds seized in 2005 were 1,205 kg while this year it was 538 kg. The seizures included tablets like alprex and ecstasy also.
Home Ministry officials said intelligence inputs received and seizures affected indicated trafficking of heroin into India from across Pakistan border.
They said figures regarding seizure of heroin of South-West Asian origin reported by various Drug Law Enforcement Agencies during the last three years indicate that there has been an increase in trafficking of heroin from across the Indo-Pak border.
They also said West-African nationals, mainly Nigerians, have been found involved in drug trafficking in and out of the country.