India's health ministry has called for Juul Labs' electronic cigarettes to be blocked from entering the country, a letter seen by Reuters showed, potentially dealing a blow to the U.S. company's plans to tap the South Asian market.Juul has plans to launch its products in India by late 2019 as it looks to expand away from its home turf. The company has hired new executives and plans to open an India subsidiary , Reuters reported in January.Citing the Reuters article, India's top health official wrote a letter to the federal commerce secretary in February, saying necessary measures should be taken to "prevent entry of such products in our markets"."Novel products such as 'JUUL' are harmful and addictive and could potentially undermine our tobacco control efforts," Health Secretary Preeti Sudan wrote in her letter dated Feb. 18 "It is felt that the young generation would be particularly vulnerable to such products and gimmicks."Asked for a comment on the letter, Juul spokeswoman Victoria Davis said the company was "open to dialogue with lawmakers and regulators in order to help switch" adult smokers in India to a viable alternative to combustible cigarettes.Juul has previously said India was among the Asian markets under evaluation, but there were no "definitive plans".The details of Sudan's letter have not previously been reported. She also sent a copy to Prime Minister Narendra Modi's office.The commerce ministry, which is likely to be involved in discussions if Juul was to receive an India approval, did not respond to Reuters queries. Modi's office also did not respond.Juul's sleek vaping devices, which resemble a USB flash drive and offer flavours such as mango and creme, are a sensation in the United States, but have drawn tighter regulatory scrutiny due to surging use among teenagers.India has 106 million adult smokers, second only to China in the world, making it a lucrative market for firms such as Juul and Philip Morris International.However, India's regulatory environment for tobacco and electronic cigarettes is highly restrictive. The health ministry last year advised states to stop the sale or import of e-cigarettes, saying they pose a "great health risk". About a third of India's 29 states currently ban e-cigarettes.In February, India's federal drugs regulator told all states to ensure that e-cigarettes were not sold or manufactured in their regions, according to a circular seen by Reuters.Advocates for the devices say e-cigarettes are far less harmful, because users do not inhale the dangerous matter taken into the lungs through cigarette smoking. But many tobacco-control activists are opposed to e-cigarettes, saying they could lead to nicotine addiction and push people to consume tobacco.Juul has said its mission was to "improve the lives of the world's one billion smokers by offering a satisfying alternative to combustible cigarettes".Indian health secretary Sudan, however, said in her letter that products such as Juul would hurt India's anti-tobacco efforts through their "easy availability, disguised appearance and the false notion of being safe". More than 900,000 people die each year in India due to tobacco-related illnesses.