How many people were vs. how many people were there

[Brprasad]

Please explain does it require 'there' after 'were' ? If so, Why?
1) How many people were in the program
2) How many people were there in the program

[James]

I would prefer "How many people were there in the program?" If you prefer 1), maybe it's better to say: How many people were involved in the program? 1) still works, though.