You are doing a good deed by spreading awareness on electricity conservation. Here are some slogans that you could use on your posters:

• Keep the future bright, Turn off the light.

• Today’s Wastage is Tomorrow’s Shortage. Give the earth a hug, pull the plug.

• Conservation: It doesn’t cost. It saves.

• Please save the power for the next hour!

• You Have the Power to Conserve.

• A unit saved is unit energy gained.

• The Less You Burn, The More You Earn

• Energy Misused cannot be excused.

In addition, you could provide information about the Earth Hour and when it is to be observed next in India.