Why is the Govt insisting on using 24 hr PSI?

For all practical and commonsensical reasons, the people want a current PSI number to make decisions on their daily activities. For all the nonsensical and unbelievable reasons, the Govt keeps on telling the people that the best reading of the PSI is the 24 hr one and 3 hour is second best. They are not going to give to the people the current PSI that the people want. Why?

I only have one