As the number of Mexicans without drinking water climbed to roughly half a million on 15 April after an oil spill, authorities in the southeastern Mexican state of Tabasco were moving to get water purification and treatment plants reopened.

The trouble began at the end of last week, when trespassers reportedly slashed an oil pipeline, which in turn polluted local waterways including the Sierra River.

As a result, four water treatment facilities were shuttered. Pemex, the national oil company, dispatched workers to try and protect drinking water. Any solution, however, is days into an ongoing hardship for locals.

"The damage is terrible. Of course we want to avoid the contamination of drinking water processing plants, but the environmental damage is indisputably going to be very big regardless," said Humberto de los Santos, mayor of Centro.

The efforts to reopen the water treatment plants began on 14 April, and by 15 April, two of the plants were reopened, according to local media reports. The incident has a taken a toll on locals.

"Well, they (authorities) told us to be prepared for water shortage but we didn't think it was going to turn into a chaos. Partly it's our responsibility for leaving everything to the last minute but much of the blame is the Pemex company's," said local resident Ericka Sanchez.

The other two plants are slated to open by 17 April. The total clean-up could take as much as 15 days. Local authorities have called on Pemex to foot the bill for the damages.