This article originally appeared on VICE Indonesia.

“Dangdut is the music of my country,” sings Indonesian group Project Pop. The genre—which blends elements of Arabic and Malay pop—is often associated with the masses and has the power to unite Indonesians.

However, dangdut has been causing a commotion lately, all because Indonesian fishermen use illegal transmitters to listen to dangdut songs on local radio stations. They do this to kill time while fishing on the high seas, but it turns out that it’s not only them who can hear the music. Pilots whose planes pass overhead do too, and have complained that the radio waves could disrupt their aircraft’s landing.

In the first six months of 2019, there were at least 18 complaints made by international pilots. They said they’re worried about local radio waves emitted by uncertified transmitters, which can result in a plane crash if the aircraft that is about to land picks up the signal.

Ismail, the Director General of Resources and Equipment of Post and Information Technology (SDPPI) of the Ministry of Communication and Information, admitted that this problem has become a hot topic in the international aviation community.

“Fishermen use uncertified devices that interfere with aircraft navigation systems. The songs they listened to reached the pilot above them. International airlines often complain about this,” Ismail told local media on Thursday during the Innovations of Frequency and Standardization Festival (IFaS-Fest).

Some fishermen say they have to use their own transmitter due to the poor quality of telecommunication services on the coast and at sea. Apart from listening to dangdut, they also use walkie-talkies to interact with other fishermen.

The Ministry of Communication and Information (Kemkominfo) has yet to trace how many pirate radios are used by the fishermen. The only thing they can do now is warn the fishermen not to use walkie-talkies, repeaters, and jammers carelessly because they could have fatal effects on flights.

They urged the fishermen to license their radio frequency, and use certified devices only. Once the permit is issued, the device must be used accordingly.

The registration process can be done online. Mobile offices where people can apply for the license are also available in coastal areas in eight provinces including West Java, Jakarta, Central Java, Makassar, and East Java, among others.

“Fishermen need a communication device with radio frequency, so we provide licensing services for those who want to have a certified and standardised radio with legal frequency. The licensing process can be done online, from submitting the application to adding a digital signature,” Ismail told website Liputan 6.

But where do the fishermen get the uncertified devices in the first place?

Uncertified devices cannot be sold without permission from the Kemkominfo, but according to Irawati Tjipto Priyanti, the Head of the Sub Directorate for Monitoring and Control of Post and Information Technology, they are offered on many e-commerce websites.