International Solar Alliance

Also called: ISA · Topic: Energy Resources of India: Conventional and Non-conventional · NCERT: Class 7, Ch 2 "India and Her Neighbours"; Class 8, Ch 1 "Natural Resources and Their Use"

Meaning

The International Solar Alliance (ISA) is an international organisation that India and France launched at COP21, Paris, on 30 November 2015. It helps countries, especially developing countries, get the finance and technology they need for solar power. It is now a treaty-based intergovernmental body with its headquarters in Gurugram, Haryana.

It matters because it is the first treaty-based international body with its headquarters in India. It also carries India's solar agenda to the Global South (developing countries in Asia, Africa and Latin America).

Explanation

How it began and became a treaty body

• Launch (cause): India and France started the ISA at COP21, Paris, on 30 November 2015. This was the same climate meeting that produced the Paris Agreement.
• Process: each country had to ratify the ISA Framework Agreement. To ratify means a country formally agrees to be bound by a treaty.
• Result: in December 2017, Guinea became the 15th country to ratify. With this, the ISA became a treaty-based international intergovernmental organisation [4].
• So the ISA was launched in 2015, but it became treaty-based only in 2017.

Who can join: from tropical countries to the whole world

• Original idea: it was meant for sunshine-rich countries lying between the Tropic of Cancer and the Tropic of Capricorn.

• The sun's rays fall almost straight down in this belt, so it gets strong sunshine for most of the year.

• 2020: membership was opened to all UN member countries.

• Growth of membership:
• November 2021: the USA became the 101st member [6].
• November 2024: 120 signatory countries, of which 102 had ratified and become full members [5].
  • A signatory has signed the agreement. A full member has also ratified it.
• 8th ISA Assembly (New Delhi, 2025): representatives from 137 countries attended [7].

What it does

• Main job: it gathers finance and technology for solar power in developing countries.
• Its work includes [5]:
• readiness and enabling activities, which help countries prepare to start solar projects;
• risk mitigation, which makes solar projects less risky for lenders, so banks and investors are more willing to fund them;
• new ways of financing solar projects.

Linked idea: One Sun One World One Grid (OSOWOG)

• India's idea, proposed in 2018.
• Logic: "the sun never sets."
• Link solar grids across time zones, for example West Asia, South Asia and South-East Asia.
• The sun is always shining somewhere along this chain.

• Power can then flow from regions in daytime to regions at night.

• Launched with the UK as the Green Grids Initiative – OSOWOG at COP26, Glasgow (2021).

Where it occurs

• Headquarters: Gurugram, Haryana (India).
• Founders: India and France, at COP21, Paris (2015).
• Core region: sunshine-rich countries in the tropics, between the Tropic of Cancer and the Tropic of Capricorn. The Tropic of Cancer passes through India.
• Present reach: open to all UN members since 2020. Members include the USA (101st member, 2021) [6]. The 8th Assembly, held in New Delhi in 2025, had 137 countries [7].
• OSOWOG grid zones: West Asia, South Asia and South-East Asia, linked across time zones.

Don't confuse with

• OSOWOG / Green Grids Initiative: India proposed OSOWOG in 2018, and it was launched with the UK at COP26 Glasgow (2021). The ISA was launched with France at COP21 Paris (2015).
• Launch year vs treaty year: the ISA was launched in 2015, but it became a treaty-based body only in December 2017, when Guinea became the 15th country to ratify [4].
• Panchamrit (COP26, 2021): these are India's own climate pledges, including net zero by 2070. The ISA is an international organisation of many countries, not a national pledge.
• Green Energy Corridor (2015): this is a domestic transmission network that carries renewable power into India's national grid. The ISA works internationally on finance and technology for solar power.

Prelims Hooks

• ISA was launched by India and France at COP21, Paris, on 30 November 2015. Trap: it was not launched at COP26 Glasgow, and the UK was not a founder.
• HQ: Gurugram, Haryana. It is the first treaty-based international body with its headquarters in India.
• Treaty-based from December 2017, when Guinea became the 15th country to ratify the Framework Agreement [4].
• Membership was opened to all UN members in 2020. Before that, it was meant for countries between the Tropic of Cancer and the Tropic of Capricorn.
• The USA became the 101st member in November 2021 [6]. In November 2024 there were 120 signatories and 102 full members [5].
• OSOWOG was proposed by India in 2018 and launched as the Green Grids Initiative with the UK at COP26 Glasgow (2021).

Mains Points

• Solar diplomacy for the Global South (GS-III / GS-II):
• Developing countries often have strong sunshine but find it hard to raise money for projects.
• The ISA helps through finance, risk mitigation and new financing models, making solar projects safer for lenders [5].

• Membership grew from tropical countries to all UN members (2020), with 137 countries at the 2025 Assembly [7]. This gives India a leadership role in climate action.

• Link with India's own energy transition:

• India crossed 50 per cent non-fossil installed capacity in June 2025, five years early [2][3].
• But solar works only by day, and coal still gives about three-quarters of India's electricity.

• OSOWOG tackles this problem of intermittent supply (power that comes and goes) by linking solar grids across time zones, so that daytime regions can supply regions at night.

• Limits and the way forward:

• The ISA itself mainly gathers finance and technology.
• Real gains need domestic transmission lines and battery storage, such as the Green Energy Corridors and the 12 GWh battery storage planned at Pang, Ladakh [8].
• It also needs cross-border grid links to carry solar power where it is needed.

Related concepts

• Green hydrogen
• National Green Hydrogen Mission
• Green Energy Corridor
• Non-fossil share of power capacity
• Just energy transition
• One Sun One World One Grid

Read more

• Energy transition: green hydrogen, grids, targets, the International Solar Alliance and conservation