One protester said she lost consciousness when a security guard threw a water bottle that hit her head. She suffered slight injuries to her limbs when she fell to the ground. An ambulance took her to hospital.

The owners allege that the developer didn't provide them with enough information about the level of noise around the complex before they bought homes there, and they point to a third-party assessment that said the noise level at midnight can top 65 decibels, exceeding the limit set in national regulations.

The protesters also said the developer had cancelled a shuttle bus to the city centre, resulting in their commutes doubling to four hours a day and forcing more than 1,000 property owners to line up for buses at 5am.

In a letter to the property owners last month, the developer acknowledged that the expressway noise had annoyed residents, but it told protesters in negotiations yesterday that all it could do was plant trees along the main roads to reduce the noise. The company also refused to provide more shuttle buses.

The flats went on sale in 2010 at an average price of 7,000 yuan (HK$8,575) per square metre, and most of the owners moved in early this year.

A spokesman for the developer told the Post potential buyers were all aware there was an expressway next to the community before they bought flats there. He said the company didn't know whether any of the protesters was injured yesterday.

Many young Guangzhou couples who can't afford the skyrocketing housing prices in the city centre have been forced to move to outlying areas such as Huadu.

65

The noise level in decibels at midnight around the Huadu flat complex, which exceeds national regulation levels for that time