Hanoi and Ho Chi Minh cities � Vietnam's two largest � have seen the quality of living decline as the environment worsens, said an economist at a seminar opened Tuesday.

Le Van Thanh of the HCMC Economic Institute was speaking at a two-day seminar on zoning plans for the cities concerning quality of life, held by the institute and the Human Resource Research Center of the University of Hawaii-Manoa in Hawaii.

Thanh said according to a recent survey by the US-based Mercer Human Resource Consulting to measure the quality of life in 215 cities worldwide, HCMC ranked 148th and Hanoi 155th, down one grade from last year.

According to him, city residents had seen considerable improvement in living standards in recent years but have also faced worsening environmental pollution, poor food safety and hygiene and increase of traffic accidents.