What is the significance of the date (w.e.f. 16-9-2016) mentioned in the content?
The date (w.e.f. 16-9-2016) mentioned in the context appears to be when a specific law or provision came into effect, which may have led to changes in tax collection and distribution between the Union and the States of India. The significance of this date is that it marks the beginning of the new system, rules, or guidelines related to taxes, inter-State trade or commerce, and their distribution as mentioned in the context.