(CNN) -- Singapore's pollution reached record high levels on Friday, prompting the authorities to issue health warnings. Children, pregnant women, the elderly and those with heart and lung conditions should stay inside to avoid the hazard.
Any pollution standards index reading above 300 is regarded as dangerous and potentially life threatening to the ill and elderly. In Singapore on Friday, it climbed to over 400.
The first picture shows the harbor in February 2010, the second, taken from a similar spot, was taken on June 20, 2013.