India has cleared a milestone on its journey toward tax reform. On March 29, the lower house of Parliament passed the four components of the Goods and Services Tax (GST). And since Finance Minister Arun Jaitley introduced the GST as a money bill, it needed the approval of only the lower house, where Prime Minister Narendra Modi's Bharatiya Janata Party (BJP) holds a majority. The vote marked a critical legislative victory for the ruling party and brought India a step closer to forging a unified market that will promote higher economic growth. Of course, the BJP still has several more obstacles to overcome before India has fully achieved tax reform. First, each of the country's 29 states must pass its own version of the GST — a lengthy process, especially for the state legislatures that the BJP doesn't control.