The European Commission has adopted new rules for drones to harmonize regulations across the 28 members of the EU and improve certainty for business.

The rules require drone operators to register with national authorities by 2020. Member states will be able to define no-fly zones where drones will not be allowed to enter. These can include airports, airfields or city centres.

The move is part of a response to incidents involving drones and fears about the safety risk they pose. In December, hundreds of flights were delayed at Gatwick airport in the U.K., near London, following sightings of drones. Around 140,000 passengers suffered disruptions to their travel plans. The drone operator has still not been identified.