China has accepted western fashion and technology as it has developed these years, but a lot of young people are turning to the past for their clothes choices and putting on traditional “hanfu”. 

as it has developed these years—— 把一个表示 “原因” 的从句，当作“时间” 从句使用，确实不当。改为过去时也不行，与主句时态不一致。建议直接使用介词短语：

During these years of development, China has accepted western fashion and technology ...

With its development these years, China has accepted western fashion and technology ...