Conversation so far:
What was Garry Kasparov towards the top of?
He was at the top of the chess world.
When did Garry Kasparov reach the top of the chess world?
Kasparov became the youngest ever undisputed World Chess Champion in 1985 at age 22.
What important matches did Garry Kasparov play to reach the top?
His first win in a superclass-level international tournament was scored at Bugojno, Yugoslavia in 1982.
When did Garry Kasparov start playing chess?
He began playing chess at age 6.
Did Garry Kasparov have any obstacles or difficulties in reaching the top?
Politics threatened to affect his matches while reaching the top.

Question: How did politics prevent him from playing?
Self-contained rewrite: How did politics prevent Garry Kasparov from playing?