Sorry, Nespresso and K-Cup lovers.

The German city of Hamburg has banned coffee pods from government-run buildings. In an attempt to become more environmentally friendly, the city said it will no longer spend taxpayer money on products that don't meet its high sustainability standards.

Coffee capsules, like those sold by the Nestle (NSRGY), Keurig (GMCR) and other brands, are specifically mentioned in the city's new guidelines, because they create unnecessary waste and contain aluminum. A spokesman for the city said the pods contain 3 grams of waste for every 6 grams of coffee.

But the list of prohibited items goes far beyond coffee. It includes plastic cutlery and plates, water, beer, and soft drinks in disposable packaging, as well as certain cleaning products and even wall paints.

"The city can help ensure that environmentally harmful products are purchased less frequently and that sustainable products achieve even greater acceptance in the market. Our objective is to increase the share of environmentally friendly products significantly in order to help combat climate change," said Hamburg senator Jens Kerstan.

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Capsule coffee machines have become increasingly popular in recent years, thanks to the convenience they offer. Euromonitor said pods have seen "colossal growth" and remain the major growth driver in the U.S. coffee market.

The National Coffee Association estimates more than quarter of U.S. households now own pod coffee makers.

But critics of the capsule coffee trend point out the pods are extremely difficult to recycle. They combine different materials, including plastic and aluminum, which can't be easily split from each other. Separating materials is crucial in the recycling process.

Some of the most popular brands behind coffee pods -- Keurig in the U.S. and Nespresso in Europe -- offer recycling options that include pick-up and drop-off service for used pods, but they don't release figures about the amount of pods that end up in landfills.

They also offer recyclable varieties of their pods, provided users are willing to do their part and separate the metal portion of the pods from the rest before recycling.

Keurig has promised to make all K-Cups recyclable, but only by 2020. "It's a very complex challenge ... the pods must keep coffee fresh before brewing, withstand the heat and pressure during brewing, and be easily punctured with a needle as part of the brewing process," the company said on its website.