Unusual footage of colourful light columns appearing in the sky above a city in northern China's Inner Mongolia on Wednesday night.<br /><br />The optical illusion was reportedly caused by tiny pieces of ice that were formed in extreme low temperatures.<br /><br />According to news reports, the weather was about -29℃ on that day which enabled the ice pieces to reflect sunlight into different colours. <br /><br />The phenomenon is rare and can only happen in certain areas in the country.
