Even though India has brought down tariffs, there still exist trade barriers that need to be done away with, visiting US commerce secretary Gary Locke said on Monday. He also urged improvements in the laws on intellectual property rights. "Though India has made tremendous strides to open up its economy, there is much more work that is left to be done," Locke told reporters at a summit organised by an industry body here. "While many tariffs have come down, others remain.