Indonesia, the world’s fourth biggest producer of cigarettes, will crack down on online tobacco advertisements in a bid to target youthful smokers, the communication minister said on Thursday. Health groups say more teenagers are taking to smoking in Indonesia, which already has nationwide curbs on cigarette ads, including a ban on sponsors’ promotion of tobacco products, though it is not consistently enforced by regional authorities. The minister said he had given orders for his team to block all online cigarette advertisements after the health minister sought the ban.