The Indian prime minister has defended his government’s controversial measure to strip the Kashmir region of its statehood and special constitutional provisions, as about 4 million Kashmiris stayed indoors for the 11th day of a security lockdown and communications blackout.

In his Independence Day address live from Delhi’s Mughal-era Red Fort on Thursday, Narendra Modi said Kashmir’s previous status – some political autonomy and a ban on outsiders buying land and taking public sector jobs in the Muslim-majority Himalayan region – had fuelled a movement for separatism and was unjust for Kashmiri women, because the law said they lost their inheritance rights if marrying a person from outside the region.

“The old arrangement in Jammu, Kashmir and Ladakh encouraged corruption, nepotism, but there was injustice when it came to rights of women, children, Dalits, tribal communities,” Modi said in the speech marking 72 years since India achieved independence from British rule.

A lockdown in Indian-administered Kashmir was put in place on 4 August, just before a presidential order to subsume the region into India’s federal government by revoking article 370 of the constitution and downgrading the state of Jammu and Kashmir into two union territories. A new law allows anyone to buy land there, which some Kashmiris fear could change the region’s culture and demographics. Critics have likened it to Israeli settlements in Palestinian territories.

India’s foreign ministry officials have said Kashmir is returning to normality, but reports from the region describe the severe constraints, including steel and barbed wire street blockades and the suspension of internet, mobile phone and landline services.

While daily protests have erupted in Kashmir, Modi has received widespread public support in other parts of India.

“Article 370 should have been removed a long time ago, but better late than never,” Amarjeet Singh, a businessman from Delhi, said outside the Red Fort as India finalised preparations on Wednesday.

“It is good. Everyone will be benefited by this, because every common man will be able to work there and start business there,” Singh said.

On Thursday, turning to his agenda to make India a $5tn economy in the next five years, Modi said the changes in Kashmir would help the region contribute more to India’s development.

“In the last 70 years we became a $2tn economy, but in the last five years, we added $1tn to the economy. This gives me the confidence of becoming a $5tn economy in the coming years,” Modi said.

The prime minister, whose Hindu nationalist Bharatiya Janata party won a landslide victory in general elections in May, also announced the creation of a new chief of defence staff to coordinate the country’s security operations.

He also made a pitch for restructuring India’s electoral system so that state and lower house of parliament elections are held simultaneously rather than on separate timetables.