It's possible that
mod_alias may not be loaded, as it provides redirect. However, then, you would expect configuration errors in the log.
It's also possible that your ProxyPass and ProxyPassReverse directives are taking precedence. If you intend to redirect, you should either put the rule on the proxied server, or remove the proxy directives. The proxy will pass the 301 redirect.
Additionally, if you redirect / to a subdirectory of itself, you will create a redirect loop. From the docs: any request beginning with URL-path will return a redirect request to the client at the location of the target URL. Additional path information beyond the matched URL-path will be appended to the target URL. This means that when the browser follows up with a request for /web/, it will get a redirect to http://in.example.com/web/web/, and so forth. Consider using RedirectMatch with an anchored regex instead. If by not working you mean that the browser complains of a redirect loop, this is the answer.