Aside from what other member have said, it's also worth to mention that few years ago some news media report Iran have limited power issue and decided to ban Bitcoin mining.
Im not sure how oftne hashrate charts are updated, im using the one in bitinfocharts and it still shows a crash.
I just visited
https://bitinfocharts.com/comparison/bitcoin-hashrate.html# and it seems their approach to smooth the graph give you wrong perception.
https://mempool.space/graphs/mining/hashrate-difficulty shows non-smoothed graph, which shows that April 24 2025 also had similar massive hashrate "drop".