The Supreme Court has ordered Punjab and Haryana to give Himachal Pradesh 11,973 million units of power arrears.
The payment will be made over the next 20 years.
Graphic: News Anek, from the facts in this report
The case is about the state's share of electricity from the Bhakra-Nangal and Beas hydroelectric projects.
These are big dams and power plants that Himachal shares with its neighbours.

The court's order is for a dispute that lasted six decades. Himachal says it has been owed its share since November 1, 1966.
Key points
- The Supreme Court ordered Punjab and Haryana to clear 11,973 million units of power arrears.
- The payment will be spread over 20 years.
- The state expects about Rs 500 to 600 crore a year at first, which could rise to Rs 1,000 crore.
- Chief Minister Sukhvinder Singh Sukhu called it the biggest Diwali gift for the state.
Why did this dispute last so long?
In November 2011, the Supreme Court recognised Himachal's right to a 7.19 per cent share in the Bhakra-Nangal and Beas projects.
That share applies from November 1, 1966.
The new order puts that 2011 judgement into effect. It sets a timeline for the arrears to be paid.
So why does this matter for people in Himachal?
The state faces a big cut in central grants. It has also lost GST compensation and the Revenue Deficit Grant.
Extra power income can help its finances.
Sukhu said the state had fought a long legal battle.
He also said the BJP leadership had not shown the same seriousness for the state's dues.
The BJP has credited the Centre and earlier governments for the outcome.
What happens next with the power supply?
The state will receive about 598 million units a year. This power is meant for the high-demand months from October to March.
The state already sells power to Rajasthan, Kerala and Tamil Nadu.
The Advocate General said the extra revenue could reach Rs 800 to 1,000 crore a year if the power sells at higher rates.
Explainer
What happened before
- Himachal Pradesh has long claimed a 7.19 per cent share of power from the Bhakra-Nangal and Beas hydroelectric projects.
- In November 2011, the Supreme Court recognised this share, which applies from November 1, 1966.
Why it matters
The state is short of money after cuts in central grants, the end of GST compensation and the stopping of the Revenue Deficit Grant. Extra power income can help its finances.
What to watch next
- Punjab and Haryana must clear the arrears over the next 20 years, as the Supreme Court has ordered.
- The Assembly polls next year will be the next political test for the state government.