A visitor takes photos of a drone made by China North Industries Group Corporation at the China Hi-tech Fair in Shenzhen, South China’s Guangdong province, Nov 18, 2015. Drones displayed by various manufacturers attracted many visitors at this year’s hi-tech fair.[Photo/Xinhua]

A drone that can take off vertically is displayed at the China Hi-tech Fair in Shenzhen, South China’s Guangdong province, Nov 18, 2015. Drones displayed by various manufacturers attracted many visitors at this year’s hi-tech fair.[Photo/Xinhua]

A drone of China’s Aviation & Aerospace Industry & Information Company is displayed at the China Hi-tech Fair in Shenzhen, South China’s Guangdong province, Nov 18, 2015. Drones displayed by various manufacturers attracted many visitors at this year’s hi-tech fair.[Photo/Xinhua]

An exhibitor (R) introduces a foldable firefighting drone to a visitor at the China Hi-tech Fair in Shenzhen, South China’s Guangdong province, Nov 18, 2015. Drones displayed by various manufacturers attracted many visitors at this year’s hi-tech fair.[Photo/Xinhua]

Visitors look at a drone of Ewatt at the China Hi-tech Fair in Shenzhen, South China’s Guangdong province, Nov 18, 2015. Drones displayed by various manufacturers attracted many visitors at this year’s hi-tech fair.[Photo/Xinhua]

Members of an exhibitor demonstrate a drone at the China Hi-tech Fair in Shenzhen, South China’s Guangdong province, Nov 18, 2015. Drones displayed by various manufacturers attracted many visitors at this year’s hi-tech fair.[Photo/Xinhua]