'Project Loon' is related to:

 a) waste management system
 b) wireless communication system
 c) solar power production
 d) water conservation technology

CSE Prelims-2016

wireless communication system. Project Loon is a research and development project being developed by X (formerly Google X) with the mission of providing Internet access to rural and remote areas. The project uses high-altitude balloons placed in the stratosphere at an altitude of about 18 km (11 mi) to create an aerial wireless network with up to 4G-LTE speeds.