Air pollution in Singapore has reached its highest level in a year 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 Thursday, cruising above the official "unhealthy" bandwidth of 100. Anything above 200 is considered "very unhealthy" particularly for young children, the elderly and those with heart and lung diseases.

Truck driver Ken Ridden, who had just arrived from Queensland, Australia, for a five-day trip with his family, says he's disappointed.

Gesturing to the barely visible city skyline, he says: "You see all the nice photos in the brochures and they look good, but there's haze around."