@chirag_rinu : check the signal strength of the wifi network that you are trying to connect.if the signal strength is good it definitely connects.if it doesnt connect then go to settings>configuration>default config. sett. and then delete the operator settings present in that now your phone must connect to the wifi network.
IF THE SIGNAL STRENGTH OF WIFI NETWORK IS NOT PROPER THEN IT DOESNT CONNECT !
you can get more info here http://discussions.nokia.com/t5/Asha-and-other-Nok