Confused by the Non-Obviousness Doctrine in Indian Patents Act

I'm stuck on Section 3(d) of the Indian Patents Act, 1970. My Papa ne kaha hai that it's a 'twist' but I'm not convinced. According to Section 3(d), a patent application can be rejected if the invention doesn't show a significant improvement over the existing one. But then, the non-obviousness doctrine comes into play, which says that an invention is patentable if it's not obvious to a person with ordinary skill in the field. But how can we be sure what's obvious or not when the same doctrine in the European Patent Convention says that an invention is obvious only if it's 'in the normal course of the job' of the person with ordinary skill? Is it just me or is the doctrine in the Indian Patents Act a bit... um, 'vague'? Help me out, guys!