Why is the bottom of this dress not smooth

How to close holes:
- Switch to Edit mode ( TAB ), switch to Edge select ( 1 ), select the border edge loop ( 2 ) by Alt-RMB-clicking on it;
- Press E to extrude, S to scale, scale it down ( 3 );
- Press Alt M and choose Collapse ( 4 );
- Switch to Vertex select, select the vertex in the middle of created geometry, optionally move it up a bit, press Shift NumPad7 to align the view parallel to it;
- Select - Select More/Less - More ( 5 );
- Shading / UVs - UV Mapping - Unwrap - Project from view* ( 6 );
- In UV editor scale it down ( S ) and put somewhere in the extra area;
- Select the same border edge again and mark it as Sharp* ( 7 ).