We all know smoking is bad for our health. But we might not have known that the cigarette filters that litter our streets also impact the environment. Esther Kentin is a lecturer at Leiden Law School. She is raising awareness of the University’s cigarette butt problem.

In the Port of Rotterdam, tiny industrial pellets leak into the environment, causing a form of pollution that’s hard to trace but highly persistent. Three students of the LDE Sustainability Honours Programme took on the challenge to identify sources of this pollution.

The university is launching a campaign to focus extra attention on our smoke-free university locations. The University is using aptly named cigarette barrels to try to show clearly just how many cigarette filters are being saved from the environment. How harmful are these cigarette filters to the e…

Nanoplastics can accumulate in developing hearts, according to a study by biologist Meiru Wang from Leiden University. Her research on chicken embryos sheds new light on how these tiny plastic particles pose a threat to our health.

Arts and leisure, Arts and leisure

Gain the knowledge and skills you need to make an impact on sustainability issues.

Some thirty Leiden students balanced on SUP boards for the Supping for Sustainability Lustrum activity. Together with alumnus Merijn Tinga, better known as the Plastic Soup Surfer, they paddled their boards through the Leiden canals and waterways, fishing plastic waste out of the water.

Life returned to something resembling normal after Covid but other crises soon took its place. These great challenges are also being felt at the University and our researchers are working on solutions. The nitrogen crisis, problems with young people’s services and an increasingly urgent climate crisis:…

Facility

In recent months, the university has been running the 'Smoke-free university' campaign because of the large number of cigarette waste on and around the faculties. As part of this campaign, gatherings were held in June, September and October to draw extra attention to this waste problem.

Marlon Titre (1982) studied at Royal Conservatoire The Hague, did his PhD and studied at Leiden University, earned several other qualifications and is now, among others, Director of Filmhuis The Hague. Who is this multi-talent?

What exactly does it mean when your doctor says you have a ‘good chance’ of survival? Leiden researchers discovered that there is a big difference in how people interpret such probability phrases. And that can be a problem, warns lead researcher Sanne Willems in her blog post.

Since 24 March, the Kamerlingh Onnes Building of the Faculty of Law has been full of hundreds of colourful jellyfish. But behind that enchanting sight is a serious message: the exhibition symbolises the loss of biodiversity in the oceans due to climate change.

What better way is there for an alderman to find out where best to put his efforts than to pay a working visit to the university? Hilbert Bredemeijer, Alderman in The Hague for Education, Sport and the Outdoor Space, paid a visit to Campus The Hague on Wednesday 6 October 2021.

Lou Boshart won the Excellence in Visual & Multimodal Ethnography Thesis Prize for his film ‘Layers of Confidence’. Lou produced a multimodal thesis about the way rat catchers in New Zealand enact conservation policies and reflect on the ethical challenges of eradicating invasive species. Xiaohui Liu…

Buurtlab 070 is a new Leiden University project in which residents, researchers and students from The Hague work together on climate, sustainability and biodiversity solutions. What do they expect of the lab?

Han Meyer, Carola Hein, Paul van de Laar and Sabine Luning, argue that in the current moment of major crises these ship channels necessitate radical reconsideration.

Taking a Bachelor’s in Security Studies while starting and running two businesses: student Mohamed Sulaiman never stops. But he wouldn’t have it any other way. PLNT The Hague entrepreneurs’ hub is a source of help and inspiration.

The course Designing Your Life helps students navigate their career pathways. As it turns out, these pathways are full of twists and turns and - as with many journeys - you only make progress once you gather the courage to take the first step.

In 2025, our colleagues from the Institute of Psychology once again made a strong presence in the media. From (inter)national newspapers to podcasts, discover where they shared their expertise in the media this year.

Are you curious about how the human skeleton works? Discover this and more on 3 October in Leiden and on 4 October in The Hague.

Exhibition

450 jaar

Annetje Ottow is stepping down as President of Leiden University’s Executive Board on 1 September 2025 after almost five years in the role. She looks back at the highs and lows – and ahead to what’s next.

How has evolution shaped our curiosity? And how does that curiosity ensure that we now have the technological ability to discover whether we are alone in the universe? This was all covered during the celebration of Leiden University’s 449th Dies Natalis.

Never before has so much research been carried out on the therapeutic effect of psychedelic drugs. Researchers at the LIBC Public Day are happy about the effect the drugs can have on depression, anxiety and PTSS, but at the same time they have some doubts. ‘The hype is bound to crash before long.’