Give some stream of consciousness and then the answer. Independence Day, one of the three National holidays in India (the other two being the Republic Day on 26 January and Mahatma Gandhi's birthday on 2 October), is observed in all Indian states and union territories. On the eve of Independence Day, the President of India delivers the "Address to the Nation". On 15 August, the prime minister hoists the Indian flag on the ramparts of the historical site Red Fort in Delhi. Twenty-one gun shots are fired in honour of the solemn occasion. In his speech, the prime minister highlights the past year's achievements, raises important issues and calls for further development. He pays tribute to the leaders of the Indian independence movement. The Indian national anthem, "Jana Gana Mana", is sung. The speech is followed by march past of divisions of the Indian Armed Forces and paramilitary forces. Parades and pageants showcase scenes from the independence struggle and India's diverse cultural traditions. Similar events take place in state capitals where the Chief Ministers of individual states unfurl the national flag, followed by parades and pageants.

Based on this passage, where does the prime minister of india hoist the flag on 15th august?
The relevant sentence in the passage is: On 15 August, the prime minister hoists the Indian flag on the ramparts of the historical site Red Fort in Delhi.
Therefore, the answer is on the ramparts of the historical site Red Fort in Delhi.