During the nineteenth century, why did upper-caste people refuse to give any information regarding the women of their household to census officials?

They believed women were supposed to be secluded within the interior of the household and not subjected to public gaze or public enquiry.

Often people themselves refused to cooperate or gave evasive answers to the census officials. For a long while they were suspicious of census operations and believed that enquiries were being conducted to impose new taxes. Upper-caste people were also unwilling to give any information regarding the women of their household: women were supposed to be secluded within the interior of the household and not subjected to public gaze or public enquiry.
Census officials also found that people were claiming identities that they associated with higher status.