xEco Polen is a mobile application available on Android that displays information on the concentration of allergenic pollen in the air. The app is developed by Dejan Lekić and is available for free. It falls under the category of Utilities & Tools and provides an essential service to people with allergies.

The app tracks the concentration of 26 different types of allergenic pollen at 25 measuring sites within the national pollen monitoring network. This data is collected from the beginning of February until the end of October, which is the period of pollen season in Serbia's climate. The app also calculates the Air Saturation Index with allergenic pollen for each allergen, which is determined through a manual method of qualitative and quantitative analysis of pollen in the air. The allergen with the highest index at a particular location defines the overall index for that measuring site.

It is important to note that the app may not start on Android 8 operating systems. In such cases, users are advised to uninstall the app and visit xeco.info/xeco/polen on their Chrome browser. A button to install the app will appear at the bottom of the page. Similarly, users with newer Xiaomi phones that have a hidden bottom navigation menu may face issues accessing the app in full-screen mode. In such cases, the app needs to be reinstalled using the above-mentioned method.