Under the RBI's asset classification norms, an asset is classified as a 'Doubtful Asset' if it has remained in the sub-standard category for a period exceeding:

💡 Solution & Explanation

Under the asset classification guidelines established by the Reserve Bank of India, credit facilities that remain in the sub-standard category for a period exceeding twelve months must be downgraded to a doubtful asset. Assets are initially categorized as sub-standard if they remain non-performing for a period less than or equal to twelve months.