Ground depression in Vietnam's Ho Chi Minh City is taking place at an alarming rate, a research report said on Tuesday. Many areas in the eight districts of the city, were sinking by five to 10 mm a year, Xinhua news agency quoted research results announced by the Vietnamese Ministry of Natural Resources and Environment and the Ho Chi Minh City University of Technology as reporting. After comparing statistics over 25 years, the city has so far sunken by some 0.4 metres, said Associate Professor Le Van Trung at the university. If attention was not paid to the depression issue, the sinking areas would face drastic depression, and some areas might even be submerged in seawater, he warned. Key reasons for the ground depression in Ho Chi Minh City include over-exploitation of underground water, rapid urbanization and effervescent transport activities. In low-lying zones, depression plus sea level rise (by an average of three mm a year due to climate change) will expand the existing inundated areas and create new ones. In coastal areas, the over-exploitation of underground water causes saltwater intrusion which negatively affects growth of plants and trees in particular and sustainable agricultural development in general.