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Wipro,TCS and Infosys are IT service companies and not exactly good sample for corporate as a whole. In IT service companies actually there is no dress code but just becuase the people do not walk in Lungi and Chappal they enforce certain dress code with pent , formal shirts , shoes and tie at-least one day in a week and ban shorts , cargo pants, 3/4 etc. For girls either western formal or Indian salwar-kameez , Sari is allowed but Short Skirts , slacks , 3/4 minis etc are banned.
In IT product companies tie looks like a sore thumb and people wear business casuals , jeans and T shirts etc. In my former Midwestern USA based company one senior guy used to dress up like Maulvi with Pathani Suit , Skull Cap and full beard but no one objective as US companies have to be very much politically correct otherwise it will become a sensitive issue. More informal companies like Google are even OK with shorts.