A group of designers aim to develop 'parasitic' drones that perch on neon billboards in Hong Kong and suck up pollution to produce fuel and grow plants. Trials for the unmanned aerial vehicle are expected to take place at airports and ports later this month, Ma Yongsheng, an aviation official who is a delegate to the National People's Congress, said.  The project is being led by the China Meteorological Administration and aviation experts, state news agency Xinhua reported. Ma is the CEO of state-owned Aviation Industry Corporation of China, which has developed the nation's first parafoil UAV, which can carry up to 700kg of smog-clearing chemicals that can be used within a five-kilometre radius. For several years, China has used aeroplanes and fixed-wing drones to spray chemicals in the air which freeze pollutants, allowing the particles to fall to the ground.