The Indian PM bragged. He loves to do it and he is a Style and Fashion Icon so does it in Style - rather fashionably. He is an anti-thesis to the previous PM who was known for his Quietude !
Apart from his Kurta, His Jacket and Personal Name in a PinStriped suit - he is setting trend with some famous Quotes ( Bytes for the Media - if you like). Recently, He called the POTUS Name. No not Names - by his Name ! He also talked about the Personal Chemistry he enjoyed with him as also with the PM of Japan, President of China and few small nations where he doled out Lines of Credit - even before the BRICS bank could take shape :). Advance booking perhaps ! He Knows ! (No, perhaps God and PM's Finance Minister also perhaps does not know). He is impulsive. He thinks on his feet.
Creates Goals without Plans and fundamentals and gives very reasonable 'Deadlines' (if they can be so called) of convenient 6 to 15 years when he may or may not be there as PM to be held accountable. I saw a 'Whispers in the Corridors" website with a Question with his photo asking "Who are Modi in 2024 ?" The Editor or Column writer must be very optimistic.
But, I digressed. Pardon these Senior moments of verbosity but we were on the subject of 'Chemistry'. Now - I wasn't very good in school in this subject and could not afford the Tutor fees by my One eyed Class teacher who had lost his one eye during a school experiment. Truly and sadly. No jokes about it. In college of course I did well with Soil Science and Chemistry and hence liked Modi's comments as they come very close with his lofty Clean Indian and Clean Ganga campaigns ( Even the Supreme Court has passed severe comments about the later one and its tardy progress ! ). 
It is said that Chemistry in a relationship is like a performance; one is electrifying and another is boring. 
It is like and Chances are high that you’re reading this because you’re in a relationship lacking in chemistry and wondering whether to stay or go. Maybe the chemistry was once there, but you no longer feel “in love.” Or it was never there and you suspect you made a big mistake.
Consider this: Maybe the real issue isn’t so much the lack of chemistry but some other problem you haven’t identified.
Much like the Hot, Warm and Cold Sales Prospects in a Salesman's Agenda Planner - As per Wikipedia, In general terms, there are 3 main types of chemistry, which are defined in terms of the nature of the rapport between the respective people:
Good chemistry - good rapport . Imagine, A time you met someone with whom you had great chemistry. In “good chemistry,” people have good rapport. Because their communication styles match or complement each other, and they make similar assumptions, it’s easy to create rapport, and they rarely bump each other out of rapport. An interaction where you expected good chemistry, perhaps because the other person was smart or physically attractive, but instead you felt no chemistry.
No chemistry - find it hard to create rapport. In “no chemistry,” people have a much harder time establishing rapport. Because of differing communication styles, habits, and assumptions, these people tend to disrupt what rapport they have.
Bad chemistry - have no rapport, or have negative rapport. In “bad chemistry,” people may be drastically out of rapport. Or they might be deep innegativerapport, where each person’s behavior triggers conflicting responses in the other .A time when you had bad chemistry with someone. You immediately felt uncomfortable or disliked them — perhaps before either of you spoke!
Now compare: How easy was it to get and stay-in rapport with each person?
There are of course various manifestations of chemistry such as: sexual chemistry, romantic chemistry, emotional chemistry, activity chemistry, team performance chemistry, creative chemistry, intellectual chemistry, and empowerment chemistry". But, I don't wish to either go there even as a digression ! :)
So What is personal chemistry, after all?
My dictionary defines personal chemistry as the emotional and psychological way two people relate to each other, especially when experienced as a powerful mutual attraction.
Example:“Their intense sexual chemistry almost tempted them into an affair.” When you’re not attracted to someone, that’s “no chemistry,” and when you dislike them on sight, that’s “bad chemistry.”
Personal chemistry = rapport

What kinds of chemistry work for you?
As you think back to your best, worst, and ho-hum relationships, notice what patterns of chemistry (or lack of it) work best for you:
What kinds of chemistry work well in your romantic relationships? Friendships? Work relationships?
Where is it important to not have certain kinds of chemistry? Since my father did intellectual work, he enjoyed not having deep intellectual rapport with my mother. It gave him a chance to rest his mind and reconnect emotionally.
Finally sharing the Types of relationship chemistry
Personally, I like to think of chemistry in terms of:
Sexual chemistry — physical attraction and rapport
Romantic chemistry — a special type of emotional rapport that generates feelings of romantic love. 
Emotional chemistry — the kind of emotional rapport you have with people you immediately like and want to be friends with.
Activity chemistry — you want to do particular activities with this person, even if you don’t have much else in common. 
Team performance chemistry — great sports teams and music groups have physical rapport that helps the players play synergistically. 
Creative chemistry — you work well creating together. 
Intellectual chemistry — When we work with equally talented people with whom we don’t have good intellectual rapport, we don’t accomplish nearly as much.
Empowerment chemistry — you could also call this spiritual chemistry.
Different Perspective:
Indian Film Industry added its own - 'Chemical Locha in the brain' for Psychological issues :) .