Python 2 and Python 3 are two major versions of the Python programming language. Python 3 was introduced as a backwards-incompatible upgrade to address several design flaws and improve the language's consistency. The key differences include:

1. Print statement:In Python 2, it uses the syntax print x whereas Python 3 requires parentheses: print(x).

2. Division operator:In Python 2, the division operator / performs integer division if both operands are integers. In Python 3, the division operator always performs true division, returning a float.

3. Unicode:Python 2 has ASCII as the default encoding, while Python 3 uses Unicode by default. In Python 3, you need to use the u prefix for Unicode strings.

4. Iteration: The range() function in Python 2 returns a list, while in Python 3, it returns an iterator. To get the old behaviour in Python 3, you can use the list(range()) construct.

These are just a few examples of the differences between Python 2 and Python 3. It's recommended to use Python 3 for new projects as Python 2 is no longer officially supported since January 1, 2020.

If you want to gain in-depth knowledge about Python 2 and Python 3, there are several Python training institutes available in Lucknow, Delhi, Indore, Noida, Meerut, Ranchi, and various cities across India. You can select the institute closest to your location for learning purposes. These institutes offer comprehensive Python training programs to help you enhance your skills and proficiency in both Python 2 and Python 3.