You very well know the mindset down here. People have not yet recognised the criticality of having a neutral accent. When people speak with a strong MTI, the listener gets irritated and the result is a huge comunication gap. Another misconception which people have, is, they mistake Neutral Accent for American Accent or British Accent. Neutral Accent purely means your communication should be understood by a person from any corner of the world in the way it should be understood.  

Having been a Voice and Accent Trainer with BPO's for over ten years, you can put people in three categories. The first category of people do not have MTI at all. The second category is the trainable category, as in, students who can be trained to come to a neutral accent. The third is the untrainable category, because they have a very strong MTI, which is extremely difficult to remove.

I personally feel, that time, is not the deciding factor. The participants need to dedicate themselves and literally make it an obsession to come to a neutral accent. They need to make it part and parcel of their routine.

I will list down the comon problems with Indian speakers in general:

They have a very fast rate of speech. The ideal speaking speed should be between 140 and 160 words per minute

They do not open their mouth while speaking, so the words are not clear and they also tend to leave out the last one or two alphabets of a word. This happens because their jaw muscles are tight

The consonant B is pronounced as P and vice versa

The consonant D is pronounced as T and vice versa

The vowel O is a major problem

The consonant L is pronounced strongly

There is no distinction made between V and W sounds

Any word having two vowels or consonants is not pulled out ( Commit )

The vowel U is pronounced without opening the mouth

There is no distinction made between the words, their, there and they while pronouncing it

The th sound is not clear

The consonant T is not pronounced sharply

Unless and until the participants do not get fully involved, it is impossible to maintain your neutral accent. They should also ensure that they speak consciously, unlike their mother tongue, which they speak unconsciously.

MTI means Mother Tongue Influence. 99% of MTI can be removed. Experienced accent trainers only can point out the MTI problems of ESL students and remove them easily.

To remove MTI is not an easy job in general. It needs lot of practice and learning because it is something that we are used to since our birth.

ref: http://www.neutralaccent.com/pronunciation.php