Taiwan’s crackdown on phone scams has led to a 70% drop in incoming international calls, representing a rare victory against unsolicited callers and highlighting the scale of the problem in the island.

The total number of inbound international calls fell to 15 million in October, compared with 50.8 million in May, according to data released by the National Communications Commission on Thursday.

Taiwan’s victory came after authorities ordered phone carriers to block overseas calls disguised as local numbers. As part of the campaign, receivers must also listen to a scam alert before picking up any international calls.

Taiwan’s campaign against nuisance calls also includes having online retailers start using codes when referring to people’s phone numbers and the creation of a dedicated “111” number from which the government would aim to text residents all official communications.

--With assistance from Cindy Wang.