Hii Kartik,
check uwsgi + django source code and pass static param in nginx and see why/how, and below is what I have found.
Env info:
python version: 2.7.5
Django version: (1, 6, 6, 'final', 0)
nginx version: nginx/1.6.0
uwsgi: 2.0.7
Env setting info:
nginx as reverse proxy listening at port 80 uwsgi as upstream unix socket, will response to the request eventually
Django config info:
USE_X_FORWARDED_HOST = True # with or without this line does not matter
nginx config:
uwsgi_param      X-Real-IP              $remote_addr;
// uwsgi_param   X-Forwarded-For        $proxy_add_x_forwarded_for;
// uwsgi_param   HTTP_X_FORWARDED_FOR   $proxy_add_x_forwarded_for;
// hardcode for testing
uwsgi_param      X-Forwarded-For        "10.10.10.10";
uwsgi_param      HTTP_X_FORWARDED_FOR   "20.20.20.20";