I am using Micromax Spark which is running on 1 GB RAM and Android lollipop 5.0.
I downloaded the game from APK Mirror. When I run it, it displays the Niantic logo and suddenly my phone restarts. This happens every time I launch the game.
I am using Micromax Spark which is running on 1 GB RAM and Android lollipop 5.0.
I downloaded the game from APK Mirror. When I run it, it displays the Niantic logo and suddenly my phone restarts. This happens every time I launch the game.
The phone probably doesn't support the game. Is there a reason (besides that it might'nt be available in your country in the Play Store) why you downloaded the game from APK Mirror?
If it's not available for your device in Play Store, then your phone could crash due to overheating while loading the game.
Adding a little more detail than "The phone probably doesn't support the game."
Your phone does not meet at least one of the suggested requirements of a "Preferred resolution of 720x1280 pixels", since the Micromax Canvas Spark has a display resolution of 540 x 960 pixels (source).
Pokemon Go uses 3D acceleration, if your phone does not have the necessary features, it will not be able to properly render the game graphics. There are options for rooted users to use software instead of hardware rendering, but they are buggy at best.