On what basis is the promoter required to withdraw the money from the separate account?

As per section 4(2)(l)(D) first and second proviso, the promoter is required to withdraw the amounts from the separate account, to cover the cost of the project, in proportion to the percentage of completion of the project. In addition, the promoter is permitted to withdraw from the separate account after it is certified by an engineer, an architect and a chartered accountant in practice that the withdrawal is in proportion to the percentage of completion of the project: