SINGAPORE: Air pollution in Singapore reached its highest level in a year on Thursday as smog from Indonesian forest fires shrouded the island nation in a veil of gray, irking tourists and alarming authorities with hours left before general elections. The Pollutant Standards Index, Singapore's main measure of air pollution, hit 160 in the late afternoon, cruising above the official 'unhealthy' bandwidth of 100, according to the National Environment Agency. Anything above 200 is considered 'very unhealthy' particularly for young children, the elderly and those with heart and lung diseases. In 2013, the same three-hour index hit a historic high of 401, way above the 'hazardous' mark of 300. 'It is a little bit disappointing. We weren't expecting this at all,' said truck driver Ken Ridden, who had just arrived from Queensland, Australia, for a five-day trip with his wife, daughter and son. 'You see all the nice photos in the brochures and they look good, but there's haze around,' he said, gesturing to the barely visible city skyline. During the week, air pollution levels have been steadily increasing, hampering campaigning for Friday's parliamentary elections. However, Singaporeans will have no choice but to vote. It is mandatory for all Singaporeans aged 21 and above to cast their vote. 'They are burning forests, it's blowing here. What can we do about it?' Prime Minister Lee Hsien Loong told the crowd at a lunchtime rally on Tuesday. He said the wealthy city-state was working with its giant neighbor Indonesia on fixing the problem, but said that they had to solve it. 'The government is cooperative, attitudes amongst the community, something different,' Lee said. In January, Indonesia ratified a long-awaited regional agreement on haze pollution that is binding on all 10 members of the Association of Southeast Asian Nations. The agreement calls on Indonesia to take steps to ease the problem through efforts of its own and international cooperation. If not, it can be held liable for the impact of haze on its neighbors. '(It is) a little disgusting,' said Taiwanese student Chang Chun Wei, who felt the haze affected his experience of local attractions. 'Last time I came here is very clean, just not like this time,' he added.