Heavy showers in Islamabad on Wednesday triggered emergency drainage operations on the capital's major arteries after underpasses at Faizabad, Zero Point and Kashmir Highway accumulated significant standing water.

Capital Development Authority and Metropolitan Corporation Islamabad teams worked through the afternoon to clear blocked outlets, while traffic police diverted commuters away from the worst-hit stretches of the Srinagar Highway.

Officials said pre-monsoon de-silting was 70 per cent complete and warned residents in low-lying sectors to avoid storm-water nullahs over the next 48 hours.