How to cut down your email pollution and why digital cleanup day matters

What is Digital Cleanup Day?

Digital Cleanup Day is a day dedicated to cleaning up our digital lives, just like we clean up our physical environment on World Cleanup Day. Now in its sixth year, it is aimed at raising awareness about digital pollution and encouraging individuals and organisations to declutter their online presence.

Since its launch in 2020, Digital Cleanup Day has brought together over 1,7 million participants across 175 countries and territories, who have collectively deleted over 16.8 million GB of data - preventing the annual production of around 3,360 tons of CO₂.

The scale of the problem

In 2026, approximately 392.5 billion emails are sent and received worldwide every single day, which works out to over 3.13 million emails per second. And the number keeps growing. Meanwhile, the wider digital world is accumulating a staggering environmental footprint. The ICT sector (digital and technology combined) is now estimated to contribute roughly 2-4% of global CO₂ and greenhouse gas emissions - a share comparable to aviation in some reports, and one that is rising with growing demand from cloud services, AI, and streaming.

Data centres alone are projected to double their electricity consumption by 2026 if current growth continues. And here is a striking fact: roughly 85% of all data stored by organisations is 'dark data' - information that is collected and stored but never actually used. Globally, this unused data generates more than 5.8 million tonnes of CO₂ every year, roughly equivalent to the annual emissions of 1.2 million cars.

Why are emails so bad for the environment?

Every online activity result in a few grams of carbon dioxide being emitted due to the energy needed to run your devices and power the wireless networks you access. In parallel, the data centres and vast services required to support the internet are also highly energy intensive and must be kept constantly cool to avoid overheating.

Sending an email causes CO₂ emission. According to Mike Berners-Lee's book The Carbon Footprint of Everything, a normal email has a footprint ranging between 0.03g and 26g of CO₂. This can rise to 50g with the addition of a large attachment - the same amount as using five plastic carrier bags. When you sent that cat video to your family and friends, it was funny, but did you realise it also released around 50g of CO₂ into the atmosphere?

Storage adds to this too: keeping an email in your inbox for a year produces on average 10g of CO₂, because the infrastructure behind every message (electricity, cooling, transmission) never really switches off.

Spam emails: a serious issue for the planet

In 2025, spam made up about 44.99% of all global email traffic, according to the Kaspersky annual Spam & Phishing Report. Independent email research estimates that roughly 170.9 billion spam emails are sent every day worldwide - underlining the massive scale of the problem. Mailboxes are saturated and polluted with messages that nobody reads, all sitting in storage, consuming energy around the clock.

The good news? Since 2011 the share of spam has decreased significantly, as filters have become smarter. But the sheer volume continues to grow. Devices and data centres are also becoming more efficient - yet the relentless rise in the number of emails means the issue of internet pollution is still expected to grow rapidly as digital transformation touches every aspect of our lives.

How to cut down your email pollution

A digital cleanup is free, takes just a few minutes. Starting by deleting old emails and unsubscribing from intrusive newsletters are small choices that can save a few grams of CO₂ per message - small individually, but meaningful at scale. Here is how to get started:

Clean up your mailbox

• Filter emails by the oldest first and archive what matters. Select long conversations, keep the most recent, and delete everything else.
• Unsubscribe from newsletters you no longer read. Many email hosts now offer one-click unsubscribe options.
• Search for common names, addresses, or words to round up similar emails and deal with them in bulk.
• Regularly empty your recycle bin and spam folder to free up server space and reduce CO₂.
• Download an anti-spam tool to intercept junk before it even arrives.

Develop better sending habits

• Write concisely and keep messages as brief as possible.
• Hyperlink files or information held online rather than adding large attachments.
• Only subscribe to the news services you genuinely want.
• Avoid sending unnecessary emails. If something can be confirmed with a colleague via a quick conversation, that is always the greener option. Tools such as Slack, Teams, and Basecamp also tend to consume less energy than email.
• Abstain from sending 'Thank you' emails that add no information.
• Think about the volume of recipients. Having unnecessary people on an email chain increases the chance the message sits in storage unread, consuming energy.
• Keep mailing lists up to date so you are not sending to stale addresses.

How to go beyond the Inbox

Email is just one part of your digital footprint. Digital Cleanup Day encourages participants to go further:

• Clean up your smartphone: remove unused apps and delete duplicate photos and videos. Idle apps consume small amounts of energy; cumulatively across millions of devices, this adds up.
• Sort your computer hard drive: delete files that are duplicates or no longer useful. Archive the important ones.
• Rationalise cloud storage: keeping 1 TB of data in the cloud for a year could use 40-70 kWh of electricity, roughly the energy needed to run a fridge for several weeks. Back up only what you truly need.
• Turn off video during virtual meetings when it is not essential, reduce streaming quality, and be more intentional about the content you create and store.

Small changes in your internet habits - deleting, unsubscribing, archiving - add up to something meaningful. Start your digital cleanup today.