How to smooth the slope of the Surface plot in Y direction?

While using the surf command to plot x,y and z data of 3 curves C1,C2 and C3 as shown in attachment file(see in image.jpg (a)) the surface generated is very smooth in x-direction (image(b)) but in y-direction the surface (looks like stairs) is not smooth(image(c)).

%The XYZ, xq, yq and vq data are in attachments.
mesh = 100;
x_lim = [0 0.2];
y_lim = [1 3];
x_mesh = (x_lim(1,1)+x_lim(1,2))/mesh;
y_mesh = (y_lim(1,1)+y_lim(1,2))/mesh;

x= XYZ(:,1); y= XYZ(:,2); z=XYZ(:,3)';

[xq, yq] = meshgrid(x_lim(1,1):x_mesh:x_lim(1,2), y_lim(1,1):y_mesh:y_lim(1,2));
vq = griddata(x,y,z,xq,yq,'natural');
xlim([x_lim(1,1) x_lim(1,2)]);
ylim([y_lim(1,1) y_lim(1,2)]);

h = surf(xq, yq, vq,'FaceAlpha', 0.9);
zlim([50 100]);

Can someone please help to understand the problem and to get a smooth curved surface in y-direction as well? Any suggestion will be a big help!!