Best of the week: corals that recover, girls living longer and a cleaner Thames

Every Sunday we round up the good news that made the biggest splash this week, plus the best pieces we published. Each full story links to its original source.

1. Corals that recover by touching

Stanford scientists found in the lab that a bleached coral gets its algae back when it touches a healthy clone: all five fragments in contact recovered within seven weeks, while those kept apart died. It was a small experiment, still a long way from the reef. Read the story

2. Girls’ health improves in 178 countries

The first World Girls’ Index shows that deaths among girls aged 5 to 19 fell from almost 1 in 800 in 2000 to 1 in 1,700 in 2023. Some 290 million girls still live in countries with low scores. See the data

3. Indonesia: extreme poverty from 86% to 3.7%

In 1984, 86 in every 100 Indonesians lived on less than $3 a day; by 2025 it was fewer than 4, according to Our World in Data. That is around 130 million fewer people in extreme poverty. See the data

4. 86% less sewage in the Thames

London’s 25km super sewer cut overflows into the river from more than 21 million to under 3 million cubic metres in 2025. The figure is the companies’ own modelled estimate, in a dry year. Read the story

5. More giant tortoises than people in the Seychelles

A study puts the giant tortoise population of Aldabra Atoll at almost 183,000 – against around 123,000 people in the whole country. In the 19th century fewer than 1,000 were left. Read the story

6. Bogong moths are back

Australia’s bogong moth lost an estimated 99.5% of its population from 2017. This spring its migration is visible again across the east of the country – good news for the mountain pygmy-possum, which relies on the moths for food. Read the story

7. Animal crashes down 91% in Colorado

Five underpasses and 14 miles of fencing on Interstate 25 cut wildlife collisions by 91% in the last year studied, according to the Colorado Department of Transportation. Read the story

8. An app that works when the networks go down

Emirhan Duman, 17, from Istanbul, built Crisis Connect, a free, open-source app that hops messages from phone to phone over Bluetooth when there is no signal. Read the story

9. More steps, better teen mental health

A study of 5,515 young people wearing activity trackers found those who took more steps a day had fewer symptoms of anxiety or low mood a year later. It is an association, not proof of cause and effect. Read the story

10. Global deforestation falls 15%

The world lost 7.04 million hectares of forest in 2025, 1.2 million fewer than in 2024, with Latin America leading the way. It is not yet enough for zero by 2030, but it shows deforestation can fall fast. See the data