Kshaya Month in Hindu Lunar Calendar may happen that a lunar month will completely overlap any of the short three nirayana solar months of Agrahayana (Margashirsha), Pausha and Magha. In this case, no new moon will occur in that overlapped solar month, and thus there will be no lunar month named after this solar month. There would be a missing or “Kshaya‘ month in the lunar year.
Kshaya Month might occur at intervals as close as 19, 46, 65, 76, 122 and 141 years.
When such a Kshaya month occurs in a lunar year, there will always be two Adhika lunar months in that period, one before and after the Kshaya lunar month. One of these two Adhika months is treated as an intercalary month and other one as a true month.
Source - Chatterjee S.K., (1998) Indian Calendaric System, Publications Division, Ministry of Information and Broadcasting, Government of India.
Dershowitz N. and Reingold E.M., (1997) Calendarical Calculations, Cambridge University Press
Indian Calendars Aslaksen H. and Doegar A. Department of Physics, Faculty of Science, National University of Singapore 10 Kent Ridge Road, Singapore 117546