Zhao Jiagui, a farmer from central China's Henan Province, prefers the lights off when helping prepare dinner at a villa in Beijing's southern suburbs for her relatives.

"Why should I turn on the lights if I can see clearly enough?" she asks.

The 65-year-old is one of hundreds of millions elderly Chinese who continue their frugal ways in a era of fast economic growth and greatly improved living conditions.

For them, frugality means not only saving money but also cherishing precious daily resources. "Being able to afford the water bill does not mean you can waste water," He Shulan tells her daughter and son-in-law.

"Big cities like Beijing are short in natural resources like water, and we have no excuse to squander them," she says.

She has fitted all the lights in her Beijing home with energy-saving bulbs and habitually flushes the toilet with waste water from the kitchen.

Power, water, paper

More younger Chinese are also taking up the frugal ways to live low-carbon and energy-saving lives.

When Keke Quei hosts her weekly Sunday evening book club at her Shanghai villa, the arriving bookworms keep their jackets on.

Quei's central heating stays off, although the temperature in the 200-square-meter home is only 10 degrees Celsius (50 degrees Fahrenheit).

"I don't care about electricity bills, but the power saved. I turn off lights in vacant rooms because it is sensible," says Quei, chief executive of Shanghai-based Kinnogene Inc. a business consultancy firm.

"I don't have a car and don't plan to buy one. There are already so many cars in Shanghai, emitting so much exhaust and making people uncomfortable. And I don't want to add to the traffic," says club member Wang Qiong.

Wang walks, cycles or takes the subway.

Quei drives a Jeep Cherokee as an outdoor enthusiast, but she avoids driving whenever possible and plans to change to a smaller car next year.

"My car is not very fuel-efficient and taking public transportation for me to go around in Shanghai makes more sense," Quei says.

Quei's e-mails are all tagged "Please consider the environment before printing this e-mail."

Some city dwellers see frugality as an inconvenience, but Quei believes that a low-carbon living should be a philosophy.

Zhou Dadi, a researcher at the Energy Research Institute of the National Development and Reform Commission (NDRC), says a low-carbon lifestyle is greatly conducive to energy saving and carbon cuts, and a change in living habits is inevitable to build a low-carbon society.

"A high-end lifestyle equals a high energy-consuming lifestyle. We don't need to live like monks, but a low-carbon life and the traditional Chinese virtue of frugality are commendable," Zhou says.

"The luxury lifestyles of some Westerners are unsustainable and must not be repeated in China," says Li Ang, climate and energy campaigner for Greenpeace China.

It's hard for the newly-affluent to take environmental actions on their own -- cutting out air-conditioning and motoring -- especially in a developing country like China, so such moves should be praised, Li says.