A practice at India's largest private lender HDFC Bank Ltd. to levy a "processing fee" on loan applications submitted with fraudulent documents is raising eyebrows. A whistleblower—one who has in the past brought to light alleged malpractices at the bank's vehicle-lending division—has written to the regulator suggesting that HDFC Bank, in return for a fee, was allowing fraudulent applicants to evade regulatory or legal action. The ba...