TOP leaders vowed to build a "beautiful China" in late 2012 at the 18th National Congress of the country's ruling party.But Beijing's air quality in early 2013 has shown that China still has a long way to go before realizing that goal. "If you have any respiratory diseases,please consult your doctor before you travel to China," suggests the Canadian Foreign Ministry on its website.This seemed to be good advice as Beijing hospitals saw a 30-percent increase in the number of patients with respiratory problems in the first month of 2013 as soaring pollution levels got national and international attention. The air pollution problem first made headlines on January 12,when Beijing's level of PM 2.5 (harmful particulate matter smaller than 2.5 mm) reached 30 times the level deemed safe by the World Health Organization (WHO).Statistics from Beijing meteorological authorities have announced that the city enjoyed only five haze-free days in January Official recommendations advised children and the elderly to stay home,and face masks sales skyrocketed. Meanwhile,over 30 cities around the country suffered similar "hazardous air" conditions.