Difference between Obligatory and Necessary

OBLIGATORY vs NECESSARY: NOUN

Anything indispensable
Anything that is necessary or indispensable; that which cannot be disregarded or omitted: as, the necessaries of life.
A privy; a water-closet.
A thing that is necessary or indispensable to some purpose; something that one can not do without; a requisite; an essential; -- used chiefly in the plural.
Such things, in respect to infants, lunatics, and married women, as are requisite for support suitable to station.
Bathroom, toilet, loo
Something indispensable.

Required by obligation or compulsion or convention
Binding in law or conscience; imposing duty or obligation; requiring performance or forbearance of some act; -- often followed by on or upon.
Imposing obligation, morally or legally; binding: an obligatory promise.
Obligate.
Required as part of a routine course of action or cultural expectation; predictable.
Of the nature of an obligation; compulsory.
Morally or legally constraining or binding
Requiring a matter or obligation.

Required by obligation, compulsion, or convention.
Logically inevitable.
Unavoidably determined by prior conditions or circumstances; inevitable.
Needed or required: : indispensable.
Unavoidably determined by prior circumstances
Absolutely essential
Such as must be; impossible to be otherwise; not to be avoided; inevitable.
Impossible to be otherwise, or to be dispensed with, without preventing the attainment of a desired result; indispensable; requisite; essential.
Acting from necessity or compulsion; involuntary; -- opposed to free.
Needed, required

Imposing obligation; binding in law or conscience; imposing duty; requiring performance of or forbearance from some act: followed by on before the person, formerly by to.

Such as must be; that cannot be otherwise.
Such that it cannot be disregarded or omitted; indispensable; requisite; essential; needful; required: as, air is necessary to support animal life; food is necessary to nourish the body.
In law:
Requisite for reasonable convenience and facility or completeness in accomplishing the purpose intended: as, the land necessary for building a railroad.
Naturally and inseparably connected in the ordinary course: as, necessary consequences.
Acting from compulsion or the absolute determination of causes: opposed to free. See free.
Synonyms Necessary, Essential, Requisite, Needful. The following remarks refer to the application of the words to ordinary practical affairs, not to philosophy. Necessary is so general a word that it covers all the others, and has the additional sense, which they do not have, of inevitable. Essential is an absolute word, noting that which is a part of the chief end of the action, or of every mode of bringing that end about. Requisite is less strong than essential, and needful is less strong still; yet each is strong and emphatic, applying to that which is imperatively needed. Needful generally applies to concrete, and often to temporary, things: as, knowledge of the countries visited is requisite, and even essential, to enjoyment of travel, but money is needful in order to be able to travel at all. Needful is often applied to that which must be supplied to produce or effect a perfect state or action.

Statutory, Minimum, Requirement, Mandated, Obliged, Incumbent on, Imposed, Bounden, Indispensable, Necessary, Prerequisite, Required, De rigueur, Mandatory, Compulsory

Adequate, Need, Appropriate, Sufficient, Imperative, Needful, Obligatory, Inevitable, Requirement, Indispensable, Necessity, Requisite, Essential, Required, Needed

Statutory, Minimum, Requirement, Mandated, Obliged, Incumbent on, Imposed, Bounden, Indispensable, Necessary, Prerequisite, Required, De rigueur, Mandatory, Compulsory

Adequate, Need, Appropriate, Sufficient, Imperative, Needful, Obligatory, Inevitable, Requirement, Indispensable, Necessity, Requisite, Essential, Required, Needed

But it is not obligatory in this case.
Obligatory use of local labor, plant and material.
APA the cover page is not always obligatory.
Obligatory committees needed to do businessaudit, budget etcvi.
Telugu Meaning of Obligatory or Meaning of Obligatory in Telugu.
This Act applies to obligatory insurance contracts with the specifications arising from the Act which establishes obligatory insurance.
The state obligatory standards of relevant levels of education are obligatory for all educational organizations irrespective of their form of ownership, types and kinds.
If one is performing dry ablution for an obligatory prayer, one must intend its being obligatory, though need not specify whether.
It shows that circumcision was obligatory upon him and therefore obligatory on all men.
But I feel this obligatory part is looking a lot less obligatory.

Accordingly, risk taking is necessary in infrastructure projects.
Additional documents may be required as deemed necessary.
And if necessary we can risk a jump.
HPDetermine price and source of necessary sublet operations.
If correction is necessary, do it in private.
If the answer is no, revisions are necessary.
Board deems appropriate or necessary in the circumstances.
The kinds of expertise necessary to develop decision support analysis tools differ from the expertise necessary to develop data capture and database management tools.
Retail Sale Tags, and Merchandise Tags are a necessary part of every retail store display and provide necessary information to your customers.
If it is necessary to change a term, it may be necessary to draft and incorporate an amendment or extension.