Shanghai's population might have reached 23 million, far exceeding the earlier estimates of 20 million, a demographer said on Tuesday.

"Livelihood issues", including an improved social security system and the provision of affordable housing, remain the top concerns of Chinese people, according to online polls conducted ahead of the country's annual parliamentary and political advisory sessions.

Banks' required reserves were raised by 50 basis points on Friday and further interest rate rises to tackle inflation were not ruled out by Zhou Xiaochuan, governor of the People's Bank of China.

The frequency and severity of droughts have increased over the past decade, causing heavy crop losses and posing a potentially grave threat to grain security.

More than half of the residents of Shanghai say they are dissatisfied with their wages, although more than a quarter of them have seen their pay increase in the last year.