Entry into force of tax treaty: Convention takes effect after exchange of ratification instruments, replacing prior tax agreement. The Convention requires ratification and exchange of instruments of ratification at Rome and enters into force on the date of that exchange; it applies in India to income assessable in any previous year commencing on or after the first day of April of the calendar year following the calendar year in which the Convention enters into force, and in Italy to income assessable in any taxable period commencing on or after the first day of January of the calendar year following the calendar year in which the Convention enters into force, and the 1981 Agreement ceases to have effect when the Convention becomes effective.