Hi! (Obligatory withholding of information so I don't dox myself) I do work in one of Singapore's universities: we do not have even remotely enough trained mycologists in the country to know if this is happening. I also recently participated in a small study in another Asian university where air from a few Asian countries was sampled for pollution: the air in Singapore is not as clean as a number of others (I.E. if these changes happened in Singapore they likely happened elsewhere too).
Additionally, none of the information in the article cites any scientific articles, and a lot of the images used are sourced from Wikimedia, and many of them aren't even of fungi native to Singapore; the city picture even features overwintering trees even though Singapore is sitting on the equator!!!
My personal take: Although Discover Wild Science endorses AI use for content generation with transparency and the article itself doesn't mention being AI-generated, I personally think the article reads as AI-generated. The author Maria Faith Saligumba also writes >10 articles a day which I think is frankly a ridiculous amount of information to research, organise and communicate to a layman audience. So, TLDR I think the whole article is AI-generated fake news.
I appreciate your readiness to question the integrity of information :)