The Dutch offshore restoration project, Ocean Cleanup, says it has reached a milestone. The organization's plastic catching efforts have now fished more than 200,000 kilograms of plastic out of the Pacific Ocean, Ocean Cleanup said on Twitter.
With the abbreviation (kg) both are correct because the reader can’t tell if kg is singular or plural. The link uses both 200,000th kilogram with no ‘s’ on kg talking about just the last kilo and 200,000 kilograms with the ‘s’ talking about all of the kilos. These are both factually and grammatically correct, but they mean slightly different things.
With the abbreviation (kg) both are correct because the reader can’t tell if kg is singular or plural. The link uses both 200,000th kilogram with no ‘s’ on kg talking about just the last kilo and 200,000 kilograms with the ‘s’ talking about all of the kilos. These are both factually and grammatically correct, but they mean slightly different things.