NEW DELHI—Indian Prime Minister Narendra Modi took on critics who accuse him of failing to pursue “big bang” liberalization measures to revamp his country’s economy, saying he has set a path for accelerated growth that India’s states now need to help navigate.

In an interview in his residence compound Wednesday, on the eve of his second anniversary in office, Mr. Modi said he had opened up more of the economy to foreign investment and made changes to curb corruption, fill gaps in rural infrastructure and make it easier to do business.

“I have actually undertaken the maximum reforms,” Mr. Modi said. But, he added, “I have an enormous task ahead for myself.”

In a visit to Washington early next month, Mr. Modi will deliver his message that India—the world’s fastest-growing major economy—is ready for a more prominent role on the world stage. He is to meet President Barack Obama and address a joint session of the U.S. Congress.

India traditionally has been a nonaligned country reluctant to play a prominent role in global affairs. But over the past decade, it has formed ever-stronger links with the U.S. “Today, unlike before, India is not standing in a corner,” Mr. Modi said.