If you are an out-of-state aspirant, your JEE Main ranking must be around the opening and closing range of 2936 - 12187. If you belong to the home state then your rank must fall under 14665 - 31620. To fall under this range you must score around 150 marks. 

If you are interested in Aerospace Engineering irrespective of the college, then you must consider IIST Thiruvananthapuram too. It offers aerospace engineering as its flagship course for which you must aim for around 4K rank in JEE Main by scoring 260+

PEC is still an amazing option for AE. If you score 150-200 in JEE Main, your seat will be almost sorted at PEC in their first round of counseling.

Both Mechanical and metallurgical engineering at Thapar and PEC Chandigarh have their own pros and cons. Let's list them out to opt for the best college for you. 

PEC Chandigarh:

• PEC Chandigarh has a better brand name compared to Thapar University. But Thapar is surely not far behind.
• PEC has an amazing culture that prepares its students for future career challenges.
• One can prepare well for their further MBA, Mtech, or MS entrance exams while being at PEC Chandigarh.
• Being a government college, PEC is doing a great job in its placement department. There was a 28% hike in their placement record in 2020 despite the pandemic situation.

Thapar University:

• Thapar has an amazing placement record and coding culture.
• As a brand name, it's growing up to the heights of PEC.
• If you opt for metallurgical science, you will limit yourself to few core companies or steel and other manufacturing firms.

Unless you are into metallurgical sciences it's better to opt for mechanical engineering as you can even jump into both technical and non-technical firms. 

Quick comparison:

Out of the above two, ME at PEC seems like a better option. PEC being a government institute has half the tuition fee of Thapar University which saves you a lot. If you plan on an MBA further, it's better to opt the best out of two and start preparing from the first year of your college itself.

It depends upon your expectations, your goals, your abilities, etc. The worth of doing Material Sciences and Metallurgy Engineering at PEC Chandigarh will depend on the following factor:

• If you gave your very best at the entrance exams but still could not score well enough to get a higher rank which would have given you an option for a better college or branch, then probably it is best to move on and choose the branch and the college. There will be opportunities here as well, no doubt about that.
• If you think you did not give your full efforts and you could do better in the next year, then definitely you should drop a year for better preparation. It is better to drop rather than lamenting in the future that you did not give your 100% and got stuck here.
• If you prefer engineering and you are passionate about the subject, then the college reputation and brand should not bother you much. It is about the learning you would get and not about other stuff like rankings, placements, etc. You would get plenty of options and opportunities here as well and after graduating too.
• If placements matter to you more than anything and you do not have any preference about the branch you would get, then definitely you should prefer a college with a better reputation, placements, etc.

PEC Chandigarh is not a bad college and has a legacy of close to 100 years now. It is also ranked 68 in the NIRF 2020 engineering college rankings. Take a decision based on what you want rather than superficial stats and other things.

Both the above colleges are really good, so you needn’t worry about that front. You need to first decide which field you have an interest in. If you really have an interest in CSE, only then you should go for PEC. Otherwise, mechanical is a very good branch. Moreover, DTU is known for its mechanical department.

If you are really interested in either of the branches, you should go for it, irrespective of the college you choose. You must first check if you are interested in coding/ development or automobiles, etc. But if you can’t judge your interests, you should go for DTU because Delhi life would offer you more exposure and opportunities. DTU Mechanical is an old, developed branch that is very proud of its heritage. 

The table below gives a brief comparison of the courses.

You may ask a DTU as well as a PEC student for their reviews and then decide which college you would like to go for.

One of my friends has done the same thing in the year 2010-11. He chose Metallurgy, but later, he changed his subject to IT. This rule was accepted during his time or the prior years of his admission. However, in recent days, the college management has changed the rules in the previous 3-4 years.

The college administration thought to fill up the vacant seats; however, no new seats will be crafted as per the requirements. This is why no up-gradation can be made for the new seats of the same department.

However, the previous rule is back again, in which 10% enhancement has been made considering the seating for “upgraders”. Thereby, if you want to take admission to this institute, you have to rely on this regulation to change your stream in the future. 

But you be prepared for the surprises as the college administration can change the existing rule at any time. It may be or may not be ensured depending on the present rules and regulations of PEC Chandigarh.