Why does the noise cancellation vary between subway and bus environments when using the Xiaomi Buds 5?

For your reference, the reasons are as follows:
1. The main reason is due to the earbuds becoming loose during movement and vibrations in such scenarios (subway and bus rides), which is common for semi in-ear earbuds like the Xiaomi Buds 5. If you encounter this issue, please remove the earbuds. Reposition them and adjust the fit to ensure both left and right earbuds snugly fit your ears consistently;
2. The Xiaomi Buds 5 features the latest adaptive ANC algorithm from Qualcomm, which provides optimizations for such scenarios.