How to draw a point in OpenGL ES3

Question

How do I draw a point in OpenGL ES3?

I'm using the GL_POINTS Primitive.

Vertex Data

// Position           Color
{{1.0f, 1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}}

In the Vertex Shader

gl_PointSize = 10.0;

This should render a Red Point on the Screen. But it's not getting rendered?

What is the problem? How do I fix it?