Mark your bottled water and please be sure to drink it all.

Those words can often be seen on posters placed outside conference rooms at hotels where deputies to the two sessions of the National People's Congress and Chinese People's Political Consultative Conference are staying.

Beyond the exhortation, the posters note that much bottled water is wasted simply because people will often take a drink from one bottle, set it aside and then not be able to distinguish it from other bottles left in the same place.

A woman drinks from a bottle of water with the "iWater" logo on it at the news center for the NPC and CPPCC sessions in Beijing on Monday. [Feng Yongbin / China Daily]

The new marking system, with the logo "iWater", was jointly launched by the Beijing Travel Committee, a government agency that promotes tourism in Beijing, and the leading group of Champion of the Water Alliance, a non-governmental water conservation organization.

The system is meant to enable the deputies to pick out their original drink from among others and finish it without worrying that they might have grabbed the wrong one.

In recent days, every bottle of water that a China Daily reporter saw in various conference rooms at the hotels had a green tag that a person could easily mark using his nail or something else.

At the China People's Palace, a Beijing hotel, a waitress surnamed Li, who declined to give her full name, said the Beijing Travel Committee gave the green tags to her hotel this year and asked that they be stuck on bottled water to make people more aware of the importance of conserving water.

Many deputies said they followed the instructions and duly marked their bottles.

Ma Zhengshan, an NPC deputy from Yunnan province, said at the current NPC annual session that the system offers a good means of saving water.

Coming from Yunnan, a place that suffers from droughts, he said he knows how precious water is and that he hoped more people would mark their bottled water to avoid wasting it.

According to statistics from the capital's tourism committee, Beijing will welcome more than 17 million people to various conferences this year, meaning at least 6,000 tons of water will be consumed, about 500 ml per capita.

If 10 percent of the water in the bottles needed to hold that amount was not drunk, at least 600 tons of water would be wasted every year, the statistics said.

Li said in the past she would see more than half of the opened bottled water at meetings left unfinished. Now, though, most people are taking away their unfinished bottles.

The idea of marking bottled water was introduced at the Beijing Municipal People's Congress, the capital's legislative body, in January.

Contact the writer at wangqian@chinadaily.com.cn