1960s fashion resurgence
From Tardis Wiki, the free Doctor Who reference
When the Thirteenth Doctor brought Ryan, Yaz, and Graham to 1969 in an attempt to visit Woodstock, she was able to deduce from clothing worn by passersby that they were at least in the right era, unless it was "one of the many 1960s fashion resurgences". (COMIC: A Little Help from my Friends)