You can now use Environment Variables with your AWS Lambda functions in the AWS China (Beijing) Region, operated by Sinnet and the AWS China (Ningxia) Region, operated by NWCD.

from Recent Announcements: https://aws.amazon.com/about-aws/whats-new/2019/11/aws-lambda-now-supports-environment-variables-in-the-aws-china-beijing-region-operated-by-sinnet-and-the-aws-china-ningxia-region-operated-by-nwcd/