Can you explain the significance of Section 287 regarding tax exemption for electricity consumption or sale?
Section 287 of the Indian Constitution deals with the exemption of taxes on electricity. According to this section, save in so far as Parliament may by law otherwise provide, no law of a State shall impose, or authorise the imposition of, a tax on the consumption or sale of electricity (whether produced by a Government or other persons) which is -

1. Produced in one state and consumed in another state.
2. Imported from a foreign country into India.
3. Exported from India to a foreign country. 

This means that states are not allowed to tax electricity in the situations mentioned above, unless otherwise provided by the Parliament through a law.