MOSUL, Iraq: Up to 500,000 civilians in Mosul are facing a “catastrophic” drinking water shortage, the United Nations warned, as Iraqi forces advance against the Islamic State group in the city. Already suffering from a severe lack of food and electricity, civilians in Iraq’s second city are now also running out of drinkable water, said Lise Grande, UN humanitarian coordinator in Iraq. “Nearly half a million civilians, already struggling to feed themselves day to day, are now without access to clean drinking water. The impact on children, women and families will be catastrophic,” Grande said on Wednesday. Tens of thousands of Iraqi troops and allied forces launched an offensive last month to retake Mosul, which was seized by IS more than two years ago.