Indian police are investigating a car explosion in New Delhi under the country’s primary anti-terrorism law as a pall of gloom descended over the capital on Tuesday. Exasperated families at a hospital were anxiously waiting for news of their loved ones after the blast near the landmark Red Fort killed at least nine people on Monday evening. The Unlawful Activities (Prevention) Act is used to investigate and prosecute acts related to “terrorism” and activities that threaten India’s sovereignty...