Hi Alex,
Nice to meet you here!
For ATC, I found this article about the atc frequencies in China on forum Zhihu: here
For search & rescue, I learnt that the frequencies are 433.000 MHz, 433.500 MHz, 438.500 MHz (also for hams) in UHF, and 145.000 MHz in VHF.
For taxi & metro, I am not very sure to be honest... perhaps some taxi drivers use local ham frequencies for communication.
By the way, if you are looking for local repeater frequencies, there is a shared document listing all the repeater frequencies on QQ (unfortunately I don't have that - hopefully other hams will provide it), or you can use one of many mini programs on WeChat, such as "业余无线电工具集", for searching.
I'm not sure if you know these... anyway, I have some tips in case you don't -
p.s. I think it is necessary to tell you that there are some related laws about listening to frequencies in China. If you are using amateur radio station for receiving, then be careful:
第四十三条 任何单位或者个人不得使用业余无线电台从事下列活动：
Article No.43 No unit or individual may use amateur radio stations to engage in the following activities:
……
（四）故意收发业余无线电台执照载明事项之外的无线电信号；
#4 Intentionally receiving and sending radio signals other than those stated in the amateur radio station license;
（五）传播、公布或者利用无意接收的信息；
#5 Disseminate, publish or utilize information received unintentionally;
……
《业余无线电台管理办法》, Ministry of Industry and Information Technology of the PRC
There were some people who listen to ATC using amateur radio station, recorded the video, uploaded on social media and eventually got caught by monitor agencies.
p.p.s. In some provinces, UHF is prohibited from usages of hams (e.g. Zhejiang). So if you are in one of them, be careful when using UHF band!
Anyway, I hope these information would help you a little... hope you a great time and a great memory here in China! Enjoy yourself and have fun!
BG5CVB