Section 47(1)(a) in The Corporation of the City of Panaji (Election) Rules, 2004
(a)any ballot box used at a polling station is unlawfully taken out of the custody of the Presiding Officer or the Returning Officer, or is accidentally or intentionally destroyed or lost, or is damaged or tampered with, to such an extent, that the result of the poll at that at polling station cannot be ascertained, or