A 100 W light bulb left on for half an hour creates enough CO2 to fill a party balloon! In the UK 920,000 tonnes of CO2, enough to fill 180,000 hot air balloons, is produced every year by lights being switched on unnecessarily! This costs the UK pounds 140 million a year! from: Energy Saving Trust.
In India weddings of the rich and powerful, use so many lights that one can only imagine how much CO2 they create! Then there are the temples, the functions, the parties, the religious and other festivals that use lighting like crazy!
We can all use energy efficient spotlights instead!