diff --git a/docs/api.md b/docs/api.md
index 6c38fde6ee2..fcc911360ab 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -147,11 +147,10 @@ Puppeteer is a Node library which provides a high-level API to control Chromium
 
 ### Environment Variables
 
-Puppeteer looks for certain environment variables to aid its operations:
+Puppeteer looks for certain [environment variables](https://en.wikipedia.org/wiki/Environment_variable) to aid its operations:
 
 - `HTTP_PROXY`, `HTTPS_PROXY`, `NO_PROXY` - defines HTTP proxy settings that are used to download and run Chromium.
 - `PUPPETEER_SKIP_CHROMIUM_DOWNLOAD` - do not download bundled Chromium during installation step.
-
 ### class: Puppeteer
 
 Puppeteer module provides a method to launch a Chromium instance.