Tonnage tax option allows qualifying companies to compute income from operating qualifying ships on a tonnage basis. A tonnage tax company is a qualifying company that may elect to have income from operating qualifying ships computed under Chapter XII-G and deemed to be profits and gains of that business. A qualifying company must be an Indian company with effective management in India, own at least one qualifying ship and have as its main object the business of operating ships. The tonnage tax option is exercised by application to the Joint Commissioner, who approves the option in writing upon being satisfied of eligibility.