A customized DJI Agras MG-1S drone flies over a rice field during a pilots training flight, as part of a test in using drone technology in the fight against malaria, near Zanzibar City, on the island of Zanzibar, Tanzania, October 31, 2019. A drone takes to the skies of the Zanzibar archipelago in the Indian Ocean - the latest technology that scientists are deploying in the fight against malaria. REUTERS/Baz Ratner

Tanzanian drone pilot Khadijah Abdulla Ali (R) flies a customized DJI Agras MG-1S drone next to DJI's Enterprise Product Manager Eduardo Rodriguez during a training flight as part of a test in using drone technology in the fight against malaria, near Zanzibar City, on the island of Zanzibar, Tanzania, October 31, 2019. The drones the researchers fly carry the innovation they say offers a new approach in fighting the deadly disease. REUTERS/Baz Ratner

Drone pilot watches a customized DJI Agras MG-1S drone fly over a rice field during a training flight being part of a test in using drone technology in the fight against malaria, near Zanzibar City, on the island of Zanzibar, Tanzania, October 31, 2019. The drones sprayed mosquito-infested rice fields, typical breeding grounds for malarial mosquitoes, with Aquatain AMF, a non-toxic colourless, solution. REUTERS/Baz Ratner

A customized DJI Agras MG-1S drone sprays water over a rice field during a pilots training flight, as part of a test in using drone technology in the fight against malaria, near Zanzibar City, on the island of Zanzibar, Tanzania, October 31, 2019. The liquid, which has been tested in laboratories but never before in the field, creates a thin film on the water's surface preventing malarial pupae and larvae from breathing at the surface, drowning and then killing them. REUTERS/Baz Ratner

A customized DJI Agras MG-1S drone sprays water over a rice field during a pilots training flight, as part of a test in using drone technology in the fight against malaria, near Zanzibar City, on the island of Zanzibar, Tanzania, October 31, 2019. REUTERS/Baz Ratner

Dji's Enterprise Product Manager Eduardo Rodriguez (C) demonstrates to drone pilots from East Africa how to fly a customized DJI Agras MG-1S drone, during a training being part of a test in using drone technology in the fight against malaria, near Zanzibar City, on the island of Zanzibar, Tanzania, October 31, 2019. REUTERS/Baz Ratner