Ninety-two, 92 children and three teachers were poisoned when a plane fumigating nearby fields sprayed a weed-killer too close to their school on Tuesday in Peru,. A health official in the municipality of Nepena told a local media that the herbicide, believed to be glyphosate, left school children vomiting and fainting. Glyphosate the active ingredient in US biotech giant Monsanto’s Roundup weed-killer has often caused controversy and confusion.

Critics have called for it to be banned, and the World Health Organisation’s International agency for Research on Cancer said last year that it “probably” causes cancer. The spraying was carried out Tuesday morning, apparently without a municipal permit.