Learn Turkish: Yaptırım olduğu halde durmadılar. - Even though there were sanctions, they did not stop.

It comes from the verb yapmak (to do). First, the causative suffix -tır is added to make yaptırmak (to compel / to enforce). Finally, the abstract noun suffix -ım is added to create yaptırım, which literally means "an enforcement" and translates as "sanction".

The English translation says "sanctions", so why isn't it plural (yaptırımlar)?

When talking about the general existence of a concept, Turkish often keeps the noun singular where English defaults to plural. Saying yaptırım here treats "sanction" as an uncountable concept or category. If they wanted to refer to specific, individual rules, they could have said yaptırımlar.

How does olduğu halde work to mean "even though"?

Hal means "state" or "situation," and the locative suffix -de makes it "in the state." Combined with olduğu (the fact that there is/was), it literally means "in the state of there being sanctions." The pattern [verb]-dığı halde is a standard B1/B2 grammar structure used to say "even though" or "although."

Could I use rağmen (despite) in this sentence instead?