Tax treaty termination requires diplomatic notice and specified advance timing, with distinct fiscal-effect dates per state. Either Contracting State may terminate the India-Chile tax treaty by diplomatic notice given at least six months before the end of a calendar year, only after five years from entry into force. Upon valid notice, termination takes effect in India for income attributable to fiscal years beginning on or after the first day of April following the calendar year of notice, and in Chile for taxes on income and related payments or expenses realized on or after the first day of January in the calendar year after the notice.