New Delhi, Sep 5 (IANS): Prime Minister Narendra Modi Friday said even small efforts can help build the nation, leave alone saving energy.

"Serving the nation does not only mean doing grand things. Doing small things is a big service to the nation," Modi said while answering a question from a student at the Manekshaw Centre here.

Modi said that the work towards serving the nation can be initiated from one's home itself.

"Ask your parents about the electricity bill, and if it is Rs.100, try to think ways of bringing it down to Rs.90," he said.

Hence, Modi said, that by saving small units of electricity one can help light a bulb in a poor person's house.

While answering another question by a student from Assam on climate change, Modi said that one should "live in harmony with nature".

"...There has been no climate change, it is us who have changed (it) and that is what has affected the environment," he said.

Laying stress on saving electricity, Modi urged students to switch off their lights on a moonlit night and enjoy its beauty and do their bit in saving power. He gave the example of Nagpur, where the mayor swtiched off street lights on moonlit nights, thereby saving electricity, and encouraged residents to come out into the streets and enjoy the glory of nature.