Environmental issues such as poor air quality and water pollution have turned away inbound tourists during the first quarter of the year, according to the Chinese tourism authority.

The number of overseas tourists to China was estimated at 31.66 million in the first three months, a drop of 1.8 percent compared with the same period last year, according to a report released on Tuesday by the China Tourism Academy, affiliated with China National Tourism Administration.

Chen Xu, a researcher from the academy, added that the revenue brought by overseas tourists was about $11.3 billion, a 3 percent drop from last year.

The data were calculated based on the figures from January and February as well as historical data from past years, Chen said. The actual figures from March will not be available till late this month.

The report was based on the national tourist satisfaction survey the academy conducted. The academy started the quarterly survey during the second quarter of 2009.

The survey is based on a questionnaire, online comments from tourists as well as complaints in the surveyed cities, Chen said.

The tourist satisfaction index for the first quarter in 2013 stood at 77.62, according to the report. The full score is 100,

Though a score above 75 means "basically satisfactory", the score for the first quarter dropped by 5.83 compared with the same period in 2012 and 9.16 compared with the fourth quarter in 2012, the report said.

Suzhou, Huangshan and Chengdu were the top three cities in terms of tourist satisfaction among the 60 cities surveyed in China, with Suzhou, Jiangsu province, receiving the highest score of 85.47, the report said.

The researchers also conducted undercover investigations for the survey, Chen said.

Air quality stood at 69.80, the lowest among all items surveyed items, while water quality stood at 73.92, the lowest public service score, the report said.

For the second quarter, the Chinese government should make policies to boost tourists' confidence, although it may be affected by the H7N9 strain of bird flu as well as other pressures, said Dai Bin, the head of the China Tourism Academy.

Dai dismissed comments that the bird flu cases will dramatically hurt the Chinese tourist market.

"It is reasonable that some countries became cautious about tourists from China. But we are optimistic about Chinese tourism development in the second quarter," Dai said.

The academy predicted that in the second quarter, the total number of tourists in the Chinese market will reach 1.76 billion, a rise of 11 percent, while revenues will increase by 13.5 percent to 1.45 trillion yuan ($233.7 billion).

Usually, the second quarter is the peak season for the Chinese tourism market, Dai said.

Compared with the SARS outbreak in 2003, the government did a good job this time and was more transparent, Dai said.

In the first quarter, the satisfaction score among overseas tourists was 80.72, a 3.59 drop from last year, the report said.

Overseas' tourists scores were far less satisfactory on air quality than domestic tourists, said Li Zhongguang, a researcher from the China Tourism Academy.

Li said other aspects such as public service, tourist agency service and prices also affected the satisfaction of overseas tourists.