Bollywood actress Vidya Balan has urged Indians not just to switch off lights during WWF's Earth Hour 2011 campaign, but to go beyond the hour and protect the earth from the issue of climate change.

The Earth Hour will be celebrated Saturday at 8.30 p.m.

"As the effects of climate change become more prevalent and more powerful, it is up to each one of us to take ownership of our collective future. WWF's Earth Hour has inspired millions across the globe and has created mass awareness on the colossal issue of climate change.

It is inspiring and encouraging to see how a step as simple as switching off lights for an hour can unite the entire world towards a single cause. I too switched off lights last year, and will do so this year as well, " Vidya said in a press statement.

The critically acclaimed actress, also added a plus sign to the '60' logo of Earth Hour. The plus signifies a commitment to add a positive act in everyday life to benefit the environment beyond just the 60 minutes.

"For Earth Hour 2011, I pledge to not just switch off but to go beyond the hour. To be mindful of conserving resources, everyday, not just for an hour. From this year on, I pledge to use energy smartly. And urge you to do so as well.

"Each one of us has the power to make a difference. We just need to be conscious of it and make wise choices. When each of us take simple steps, together these actions add up. I am supporting the fight against climate change by adopting some of these steps. It's time you do too, " she added.

Earth Hour 2011 is expected to be a culmination of over one billion people around the globe, in more than six thousand cities across 130 countries worldwide.