Mexico City ? Delegates from 130 nations opened a summit on global water supplies Thursday amid calls for massive donations to rebuild water systems in poor nations.

Participants also debated the developing world’s growing reliance on bottled water bought from private companies instead of on public water systems – which some call a form of privatization.

While outright privatization of public water systems has been a hard sell since 2000 – when mass protests in Bolivia over rate increases forced out private water companies – the private sector earns much more now by selling bottled water to people in developing countries who often don’t have drinkable tap water.