Mumbai:
The teenager sits quietly in a Mumbai rehab clinic, a victim of India's emerging fad for the drug crystal meth, which experts say is spurred by loopholes in the country's giant chemical industry.
"It made me feel powerful," said the 19-year-old undergraduate student, who began taking the drug with friends at college last year and was soon snorting up to 40 lines of the dangerous stimulant in a single session.
"We would just sit and keep doing it," he said.
While meth has long been a scourge across east and southeast Asia, staff at the rehab centre in Mumbai's Masina Hospital say it only surfaced as a concern in the city in the past 18 to 24 months.
Mumbai's Anti-Terrorism Squad (ATS) in recent weeks has taken up a "war footing" against the drug.
"It's very much a local product," ATS chief Himanshu Roy said.
"It's a new age drug, it's easy to manufacture, the ingredients are available.
India is home to one of the world's biggest chemical industries and is a major source of key meth ingredients ephedrine and pseudoephedrine, which are both legally used in medication such as decongestants.
Experts say meth's precursor ingredients are both made illegally in India and diverted from legal sources in the chemical industry, despite regulations designed to prevent this and ensure a paper trail of payments.
"There's a really strict regime but in the last 15 years there have been so many loopholes," said Romesh Bhattacharji, a member of the Institute for Narcotics Studies and Analysis in New Delhi.
India's Narcotics Control Bureau (NCB) gets quarterly returns from manufacturers, wholesalers and retailers on sales of ephedrine, but Bhattacharji said nothing is done with the information.
Vijay Kumar, the NCB's deputy director general in Mumbai, said they maintained the database of returns "to cross-check if there are any violations later", adding that they had busted four illegal meth labs since 2013 in west and south India.
But he said anyone could buy pharmaceutical products containing ephedrine over the counter in India. As early as 2007, an illicit meth lab was found in Mumbai extracting precursors from such products, according to the UNODC.
While users are drawn to feelings of euphoria and energy brought on by meth, which affects the central nervous system, excessive doses can trigger violent behaviour, convulsions and even death from respiratory or heart failure.
Meth comes in powder, pills or in the crystal form that Mumbai users said they crushed with cards and snorted, although the drug can also be swallowed, injected and smoked.
Addicts at the Masina clinic said they were buying it for as little as 1,000-2,000 rupees a gram, making it far cheaper than cocaine which cost them up to 7,000 rupees.