Wi-Fi is a wireless technology that allows electronic devices to connect to the internet without wires. It was first implemented in 2005 in Sunnyvale, California and introduced in India in 2010 in Mysore. Wi-Fi has advantages such as low cost, wireless internet access, and high data transfer rates but also has disadvantages like difficult setup, security issues, and limited range. Health organizations have stated that Wi-Fi poses little health risks from radiation exposure.