There is almost too much water in Wales. It falls steadily, shrouds hilltops and floods the fields. But in Rajasthan, in northern India, the absence of monsoons was recently causing the famous lakes to dry out.

Such are the contrasts brought home to pupils at Gors primary school as they explore environmental issues with their global partner, the Study School in Udaipur - including the exchange of data on rainfall.

The Study School is a private, middle-class school, with 600 pupils aged six to 16, well-resourced by Indian standards. Gors is a community school with 250 pupils, situated in a deprived part of Swansea. More than one in three pupils are registered as having special needs and more than half of the 43 who have English as a second language are the children of asylum-seekers.

Despite - or perhaps because of - the differences between the schools, both pupils and teachers find the link between them inspiring. They exchange video and audio tapes, and a “travel buddy”, in the form of a fluffy toy sheep called Shadwell, travels to and fro bearing a diary of his experiences, written by pupils.

“We’ve built up an incredible range of resources that has livened up our teaching on India,” says Marion Jones, the school’s co-ordinator of international links.

But it is perhaps the exchanges and links between staff that are the most valuable features of the partnership, funded by the Department for International Development through the British Council. Four staff from Gors visited Rajasthan last year and three plan to go in 2006. On his first visit to India, the head, Keith Atkins, recalls spending half a day teaching in a government-funded school with 70 in each small classroom. The pupils had walked up to nine miles across the desert to attend.

At the Study School, Mr Atkins has been impressed by the children’s enthusiastic attitude to learning - less so by the emphasis on rote learning and facts rather than opinion. Asha Singh, head of the Study School, is keen to develop a warmer, more pastoral approach to her pupils and a more thematic approach to learning, of the kind she has seen in Wales.

Mr Atkins sought out the partnership with India after reaping the benefits of links with schools elsewhere in Europe through the European Unions’s Comenius programme (also run through the British Council). The first was with schools in Sweden and Finland; now Gors is the lead school in a partnership programme with Poland, Germany, Italy and Sweden. Gors primary is one of only five schools in Wales to have won a British Council International School Award.

Mr Atkins cannot say that these links alone are responsible for the remarkable turnaround in his school’s fortunes in the last seven years.

From a struggling school, it has now become “good and improving”, says Estyn, the Welsh inspectorate. In the last five years, English results at key stage 2 have risen from just over half of pupils reaching level 4 to nearly three-quarters.

Mr Atkins believes the gains, both personal and professional, have been “immeasurable”, and he asks: “Why don’t other schools do more?”

At the other end of Wales, in the handsome market town of Llangollen on the Dee, the pupils of Dinas Bran comprehensive are used to welcoming foreigners. Llangollen is home to the annual international eisteddfod, started in 1947 to promote peace and harmony (and prevent a third world war). The 1,200 pupils are heavily involved with running the eisteddfod.

So Dinas Bran has a naturally international flavour, it has Comenius links with schools in several European countries and is another winner of the International School Award.

“Our aim,” says Alison Brown, the head, “is to have every department linked with a different country.” Technology, for instance, is linked with the Netherlands and humanities with Ireland.

Now the comprehensive has cast its net wider. It has joined up with a tiny rural primary and a special school to form global partnerships with schools in one of the poorest and most mountainous countries on earth - Nepal. The theme? Water.

Dinas Bran’s partnership is with the Shree Shanti school in Kathmandu, which is similar in ethos to a grammar school.

Mark Hughes, head of English at Dinas Bran and the chief link co-ordinator with Nepal, was struck by the high staff-pupil ratios during his 10-day exploratory visit to observe and teach at Shree Shanti. “There are 800 pupils aged six to 18 and 40 in a class,” he says. But he also commented on how happy people seemed, despite poverty and appallingly high unemployment.

Divendra Pradhan, head of Shree Shanti (and also pillar of the Red Cross, Rotary Club and much else) has just been on his second two-week visit to North Wales as part of the partnership programme.

“The teaching style is not so different,” says Mr Pradhan. “In Nepal, we are encouraged by the government to teach the British system, but if we want to do a new thing, we have a problem with the parents.”

The chief difference, he says, lies in Welsh teachers’ collegiate approach and interest in pastoral care. “In Nepal, teachers are not interested in pupils’ problems.”

Impressed with the daily staff meetings he experienced at Dinas Bran, he has now instituted group meetings of teachers before the start of school and whole-staff meetings once a month in Shree Shanti.