Complex sentence: In early 20th century, the capital of the state of Uttar Pradesh was Allahabad; a decision was taken in 1922 to move the capital to Lucknow and to construct a building there to house the Assembly Constituency.
Split into simpler sentences: In early 20th century, the capital of the state of Uttar Pradesh used to be Allahabad. In 1922, decision was taken to shift the capital from Allahabad to Lucknow and to construct a building in Lucknow to house the Assembly Constituency.