Shanghai and parts of the Yangtze River Delta are were blanketed by heavy smog on Tuesday, with officials saying cold air from northern China was carrying pollutants that were expected to reach Taiwan later in the day. The poor air quality air in the region comes after an “airpocalypse” struck Beijing and Hebei province earlier in the month. Factories in Shanghai were told to reduce production today, construction work ordered to halt and schools across the city advised to avoid letting pupils remain outside for extended periods. The municipal government issued a yellow air pollution alert this morning. Watch: Heavy smog engulfs Shanghai The city’s Environmental Protection Bureau posted an image depicting a crying doll on its website. The level of PM2.5 particles, deemed the most hazardous to human health, was 301 at 9am, according to the US consulate. Local environmental officials blamed the smog on the cold front that came down from the north, the news website ThePaper.cn reported. Nearby Jiangsu province has also been suffering intense air pollution for the past four days. The PM2.5 index in almost all of the province’s cities had exceeded 200 by the morning, according to the provincial environmental authority. The Nanjing municipal government issued a yellow alert on Monday, Xinhua Daily reported. Visibility in most parts of the province was less than 3km. The cold front was deemed a contributing factor to the Jiangsu smog but emissions from local factories were also being blamed. “These factors have led to mounting air pollution in the northern part of Jiangsu,” Tang Lili, an official at the provincial environmental monitoring centre, was quoted as saying. Hangzhou, the capital of Zhejiang province, saw its PM2.5 index climb to 201 in the morning, according to the provincial environmental authority. Li Duan, a mother of a two-year-old girl in Shanghai, said that when she went outside this morning, her nose felt full of small particles. “I checked the PM2.5 index. Seeing the extremely high number, I immediately told my parents to close all of the windows at home and to turn on the air purifier,” she said. “I told them not to take my daughter outside to play today.“ I told [my parents] not to take my daughter outside to play today Li Duan, mother in Shanghai She said she didn’t know how to explain to her why she couldn’t go outdoors. “Even on rainy days, we can play in parks, wearing raincoats. But in such weather, we can’t. It makes me really frustrated.” Taiwan’s Environmental Protection Administration said on Tuesday the strong cold front coming from the mainland was expected to bring air-borne pollutants, the Central News Agency reported. Air quality in the north of the island would be poor and residents should take preventive measures, the administration said. PM2.5 levels in some parts of the island could rise to 100 by the late afternoon. Any reading higher than 71 is regarded as “very serious”. The administration expected that by Wednesday morning the northern and middle parts of the island would experience serious air pollution, and the smog was expected to move south later in the day, United Daily News reported.