New Delhi, April 1 (ANI): The stalwart of film industry. Amitabh Bachchan turned off the lights for an hour as part of the global environment campaign. "Had put the lights off at 8:30 p.m. till 9:30 pm for Earth Day, environment campaign on March 29 at home . did you?" he posted on micro-blogging site twitter. As part of their commitment to the planet, people are asked to switch off the lights for an hour on Earth Hour, held every year in March. It's great to spread awareness Big B!!!