According to The Daily Mail, UEFA defines a 'clash' as when two teams can't compete on the same day because they share the same stadium, or city, or are within 50km of one another. However, after Tottenham and Chelsea reached the last 16 of the Europa League and Europa Conference League respectively, the London sides - whose grounds are around 16km away from each other - have been given the green light for both home matches to go ahead on March 13.