Given the task definition and input, reply with output. This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Exhibitions and annual horse shows in all districts and a national horse and cattle show at Lahore are held with the official patronage. The national horse and cattle show at Lahore is the biggest festival where sports, exhibitions, and livestock competitions are held. It not only encourages and patronises agricultural products and livestock through the exhibitions of agricultural products and cattle but is also a colourful documentary on the rich cultural heritage of the province with its strong rural roots.
What is Punjab's biggest festival?