Nijel Amos, a 2012 Olympic silver medalist in the men’s 800 meters, has been banned for three years for doping, the Athletics Integrity Unit said in a ruling published .

• The runner from Botswana tested positive for the banned substance GW1516 last year in the run-up to the track world championships and received a reduction on the standard four-year ban because he admitted to the charges.
• The ban rules Amos out of next year’s Paris Olympics. 
• Amos equaled the third-fastest time in 800 history at the age of 18 when he won the silver medal at the 2012 London Games, becoming Botswana’s first-ever Olympic medalist. His silver medal is not affected by the doping ruling. 
• The 29-year-old Amos is a three-time Olympian who has won titles at the African Championships and Commonwealth Games.