Electronic cigarette makers were counting on Asia as a growth market. But the region may not be a refuge from an escalating crackdown in the U.S.

India banned electronic cigarettes last week, days after Juul Labs Inc.’s products vanished from online Chinese marketplaces. [...] But some nations still view e-cigarettes as viable alternatives to smoking, a leading cause of preventable death. Public health officials in Britain, the biggest market in Europe for the products, endorse vaping as a way to wean people off smoking. [...]